Table of contents :

• animal : a living organism having sensation and the power of voluntary movement and requiring for its existence oxygen and organic food
• structural genomics
• modification : a mantainance methylase create N⁵-methylC (< 3-5%) in CpG box in both strands during chromosome replication using SAM as donor. Not in Insects !

• Eumetazoa
• Bilateria
• Acoelomata
• Coelomata

The discarded mucous houses of tadpole-like sea creatures called Appendicularia / Larvacea (appendicularians; larvaceans) have been revealed to be a major source of food for seafloor life. Scientists have long wondered about the origin of the food eaten by creatures that live near the ocean floor. Carbon from the remains of dead fish, plankton and other detritus of marine life is known to trickle down through the water. But measurements have indicated that this slow 'rain' of particulates is not enough to sustain the life below. Larvaceans, which can be up to 6 cm long, feed themselves by creating a giant filter sack of mucus that can reach up to a metre in length. They pump water through this sack with their tails, and feed on the captured carbon. When the filters become clogged, the larvacean discards its house and excretes a new one. The old house will sometimes collapse into a ball laden with carbon that plummets through the water. They become great big, carbon-rich, fast-moving particles the size of your fist that shoot to the deep sea floor. By measuring this process in the Monterey Bay area over 10 years, the creatures supply 7.6 grams of carbon to each square metre of Monterey sea floor in a year. That's half as much again as the carbon provided by the slow trickle of marine particulates, and is more than enough to account for the 'missing' food. The carbon content of these particles is a major percentage of what gets down there^ref. The same creatures are probably contributing carbon to the sea floor in other warm-water areas. Larvaceans and jellyfish are typically hard to study, because their delicate bodies are often cut up instead of being retrieved by nets. These creatures contribute much more to the marine cycle than previously appreciated
Web resources : The jelly zone
• Cycliophora
• Gnathostomulida
• Pseudocoelomata
• Cnidaria (cnidarians)
• Anthozoa (anthozoans)
• Cubozoa (sea wasps)
• Hydrozoa (hydrozoans)
• Scyphozoa (jellyfishes)
• Ctenophora (ctenophores)
• Cyclocoela
• Typhlocoela
• Mesozoa
• Orthonectida
• Rhopalura
• Rhombozoa
• Dicyemida
• Myxozoa
• Buddenbrockia
• Buddenbrockia plumatellae
• Myxosporea
• Actinomyxida
• Bivalvulida
• Multivalvulida
• unclassified Myxosporea
• Tetracapsula
• Tetracapsula bryosalmonae
• Tetracapsula bryozoides
• Tetracapsula sp. SG-2001
• Placozoa
• Trichoplax
• Trichoplax adhaerens
• Trichoplax sp.
• Porifera (sponges)
• Calcarea
• Calcaronea
• Calcinea
• Demospongiae
• Ceractinomorpha
• Homoscleromorpha
• Tetractinomorpha
• Hexactinellida
Hexasterophora

• dmoz Open Directory Project (ODP) : Zoology
• Reef Check
• Invertebrates
• Mollusks :

Each sea-urchin spine is made from a single crystal of calcite, a mineral mostly consisting of calcium carbonate, and can reach several centimetres in length. The crystals have a complex structure bounded by smooth, curved surfaces, unlike calcite crystals grown in the lab, which take on an angular shape with 6 flat faces, called a rhombohedron. Spines are formed in a 2-stage process involving an unstable intermediate called amorphous calcium carbonate. The sea urchins package this compound in an envelope of living cells, like icing sugar filling a squeezy bag, before it crystallizes. When marshalled into the correct spiny shape, the compound transforms into a stable crystal, although the researchers still do not know exactly how the reaction occurs. Lab-grown crystals of calcium carbonate form directly from solution without an amorphous stage, so they simply adopt their rhombohedron shape. Sea-urchin larvae are already known to use amorphous calcium carbonate during growth; the fact that adults also use it to repair damage suggests that the technique could be widespread among other marine animals such as corals and sponges. Replicating the strategy in the lab is likely to prove tricky, although the general strategy of using moulding to engineer advanced materials may prove fruitful. Interest in mimicking the processes by which minerals are formed naturally, known as biomimetic synthesis, is growing. Some material scientists are already using moulding methods to fashion simple crystals. Calcium carbonate could be used to tailor-make dental implants or bone grafts. But a bewildering range of applications could become possible if the general strategy can be applied to other materials. If you could take any material and learn how to mould it or shape it in this way, you could gain far more control over its optical, electronic or mechanical properties.
2 tiny species of tropical octopus have demonstrated a remarkable disappearing trick. They adopt a 2-armed 'walk' that frees up their remaining 6 limbs to camouflage them as they slink away from trouble. The apple-sized Octopus marginatus was filmed in the tropical waters of Indonesia. Instead of its usual sprawling crawl, O. marginatus fled from divers by striding on 2 arms, with the rest of its arms wrapped around its body, giving it the appearance of a walking coconut. By rolling its rearmost arm out along the sea bed, and then repeating the action using a second arm, the octopus walks as if it is on a conveyor belt. It's like a backward walk : looking like a coconut may help O. marginatus to go unseen. There is an abundance of coconuts on the sea floor in the area. The related species Octopus aculeatus, which has a body the size of a walnut, was also filmed walking, this time along the floor of an aquarium tank. With its arms raised about its head, the octopus looked like a clump of algae. Bipedal locomotion was thought to require muscle pulling against hard skeleton. But the octopuses walk using opposing muscle movements, a technique that requires little brain control^{ref1, ref2}
Web resources :
• Caenorhabditis elegans II by Riddle, Donald L.; Blumenthal, Thomas; Meyer, Barbara J.; Priess, James R.; 1997
• The APLYSIA project
• Gastropods, scaphopods, and cephalopods
• Opisthobranchs from around the World
Shells database (Mollusca classification).
• Annelid Resources
• Annelida
• Brachiopoda: Family level classification
• Ctenophora
• Echinoderm classification
• Monogenea
• Neogene marine biota - bivalves, gastropods, bryozoans, corals, forams, ostracodes (fossil and living).
• Sipuncula
• Stauromedusae
• Entomology : insects demonstrate a remarkable evolutionary success, with low extinction rates : approximately 800,000 insect species, about 80% of all the animal species known to date, have been identified and named.
• Insecta : a class of the Arthropoda whose members are characterized by division into three parts: head, thorax, and abdomen; there are three orders of medical interest, Hemiptera, Diptera, and Siphonaptera
• Insectivora : an order of small, terrestrial mammals, including the moles and shrews, which feed primarily on insects and other invertebrates.
• ecdysone : the hormone produced in the prothoracic glands of arthropods that induces ...
• ecdysis / molting : desquamation or sloughing; especially the shedding of an outer covering and the development of a new one such as occurs in certain arthropods, crustaceans, lizards, and snakes
• metamorphosis : change of shape or structure, particularly a transition from one developmental stage to another, as from larva to adult form.
• instar [L. “a form”] : any stage of an arthropod between molts
• larva [L. “ghost”] : an independent, motile, sometimes feeding, developmental stage in the life history of an animal
• pupa [L. “a doll”] : the second stage in the development of an insect, between the larva and the imago
• tubes called tracheae run throughout their bodies delivering oxygen. The main airways get smaller as they branch off into their tissues. The tubes open to the outside air through vents called spiracles. Insects pump their abdomens to increase airflow or fill air sacs as they fly. Compressions that occur while the spiracles are closed may speed the diffusion of oxygen into insects' tissues by raising the internal pressure.
• imago : the final or adult stage of an insect
• Drosophila wing primordium displays cells that are squamous, cuboidal, or columnar.Mutation of a signaling receptor produced a wing defect in which cells are extruded from the epithelial surface. Contrary to earlier work that implicated this signaling pathway in cell survival, it appears that the signaling pathway is instead involved in epithelial organization, and any subsequent cell death is a secondary effect^{ref1, ref2}
• at least 1 hexapod group, the Collembola (springtails), diverged from the insect line even before lobsters and crabs did, and their development of a 3-segment body plan with 6 legs is likely the result of convergent evolution rather than direct ancestry
• cercus : a rigid bristle-like appendage near the tail of most insects and some other arthropods, with varying functions including mechanoreception and copulation.
• extravagant courtship dances and ornaments are common among the dozens of different Habronattus species (e.g. Habronattus dossenus). The thrumming buzzes and bangs, produced by the beating the abdomen against the ground, may serve to reinforce the male's visual display, made by brandishing his front legs. It's unclear whether other jumping spider species found throughout North America use such seismic signals - the signals may be less effective on sand than on rock, for example.
• anal pouch : the expanded end of the hindgut in certain insects
• mitochondrial body : a fused colony of mitochondria found in the spermatids of insects.
• pericardial sinus / pericardium : an enlarged blood-filled portion of the hemocoelom surrounding the heart in many invertebrates with open circulatory systems, such as arthropods
• peritrophic membrane : a delicate, cylindrical sheath of chitin continuously secreted from the posterior edge of the foregut of insects and millipedes that ingest solid food, which surrounds the food as it passes through the midgut.
• haustellum : a mouthpart of certain ectoparasites, such as bedbugs and lice, modified for piercing and sucking, consisting of a hollow tube with an eversible set of 5 stylets, by which the organism attaches itself to the host and through which the blood is drawn up
• butterfly : any of numerous flying insects of the order Lepidoptera, or something resembling this insect
• tracheole : one of the minute, fluid-filled tubules in which the tracheae of a terrestrial arthropod terminate, which contain air cells and permeate all the body tissues. Like most other animals, insects need to inhale oxygen and get rid of carbon dioxide. Oxygen fuels energy production in the cells' power plants, the mitochondria, and carbon dioxide is released as a waste product. Contrary to what might be expected, the insect respiratory system may limit rather than assist the uptake of oxygen^ref. In insects, the exchange of gas with the atmosphere is restricted by a mostly impermeable and inflexible outer layer — the cuticle. Therefore, insects have small openings called spiracles in their cuticle. These are connected to the inner organs by a system of highly branched, gas-filled tubes called tracheae. Oxygen uptake and carbon dioxide release by the cells mainly occur at the tips of the smallest branches. In highly active organs, such as flight muscle, the tracheal endings can even enter the cells and reach the mitochondria directly. A common misconception is that the insect's tracheal system is a very inefficient transport pathway. In fact, oxygen and carbon dioxide are respectively delivered about 200,000 times and 10,000 times faster in tracheal air than in the aqueous environment of the blood. Therefore, simple diffusion through the tracheae would probably be sufficient to supply adequate oxygen and remove carbon dioxide waste even in the largest insects known historically (for example, the dragonfly Meganeura monyi, which lived about 280 million years ago and had a wing-span of 70 cm). The spiracles in the cuticle behave like valves, opening and closing to allow or restrict the insect's gas exchange. Physiologists have long been puzzled by a peculiar rhythmic respiratory behaviour referred to as the discontinuous gas-exchange cycle (DGC)^ref. In insects exhibiting DGC, the spiracles close for long periods (up to several hours or even days) and open occasionally for only a few minutes. This unusual respiratory pattern has been observed in many adult insects, as well as in resting butterfly and moth pupae. Two main hypotheses have been proposed to explain why some insects display DGC: to reduce water loss through the spiracles, or to adapt to an underground lifestyle. But these ideas were disproved on closer inspection because DGC could be associated with neither the humidity nor the carbon dioxide concentration^ref of the environment. Hetz and Bradley propose a different theory to explain DGC, and their hypothesis has far-reaching implications for how we view animal respiration. They provide compelling evidence that insects use DGC not to acquire but to avoid oxygen. Using the pupae of the moth Attacus atlas as a model system, the authors varied the environmental oxygen concentrations from partial pressures of 5 to 50 kPa (the normal atmospheric oxygen partial pressure at sea level is about 21 kPa). Nevertheless, the intra-tracheal oxygen levels in the resting pupae remained low, close to 4 kPa, across the whole range of partial pressures. Thus, the moth pupa limits the amount of oxygen taken in by keeping the spiracles closed for as long as possible, and opening them only to get rid of the accumulated carbon dioxide. At first glance, the idea that an air-breathing animal should try to limit apparently normal oxygen levels seems perplexing. But oxygen is a double-edged sword: although required to fuel energy production, it is also a potent source of toxic compounds known as reactive oxygen species (ROS), which can damage proteins, DNA and lipids7. In recent years, ROS have been recognized as a major threat to cell survival, and toxic ROS effects are suggested to underlie aging and cell death. Therefore, it is advantageous to keep cellular oxygen levels just high enough for efficient mitochondrial respiration, and as low as possible to minimize oxidative damage. Obviously, the critical oxygen concentration in moth pupae is far below the normal atmospheric level of about 21%. This is probably true for other animals too; for instance, quite low oxygen levels (0.4–5 kPa) are also found in mammalian tissues8. But if atmospheric oxygen concentrations are toxic to resting pupae, why aren't they noxious to the insects that rarely or never close their spiracles? The answer probably lies in differences in metabolic activity. The insects' tracheal system is well designed for efficient oxygen supply during periods of high activity, when oxygen never accumulates to critical concentrations in the cell because it is rapidly converted into water by the respiratory chain. However, in periods when respiration falls, such as in the resting butterfly pupa, oxygen consumption is too low to prevent it building up to harmful levels. It seems that a particular breathing pattern, the DGC, has evolved to ensure oxygen homeostasis. Insect breathing apparatus. Top, the tracheal system of the beetle Zophobas rugipes; below, a spiracle of the same species


Insect societies are vulnerable to exploitation by workers who reproduce selfishly rather than help to rear the queen's offspring. In most species, however, only a small proportion of the workers reproduce. 2 key factors are identified in an evolutionarily stable strategy (ESS) model to investigate factors that could explain these observed low levels of reproductive exploitation : relatedness and policing. Relatedness affects the ESS proportion of reproductive workers because laying workers generally work less, leading to greater inclusive fitness costs when within-colony relatedness is higher. The second key factor is policing. In many species, worker-laid eggs are selectively removed or 'policed' by other workers or the queen. Policing not only prevents the rearing of worker-laid eggs but can also make it unprofitable for workers to lay eggs in the first place. This can explain why almost no workers reproduce in species with efficient policing, such as honeybees, Apis, and the common wasp, Vespula vulgaris, despite relatively low relatedness caused by multiple mating of the mother queen. Although our analyses focus on social insects, the conclusion that both relatedness and policing can reduce the incentive for cheating applies to other biological systems as well^ref. There are three major classes of insect genetic systems: those with diploid males (diplodiploidy), those with effectively haploid males (haplodiploidy), and those without males (thelytoky). Mixed systems, involving cyclic or facultative switching between thelytoky and either of the other systems, also occur. Obligate thelytoky has arisen from each of the other systems, and there is evidence that over 900 such origins have occurred. The number of origins of facultative thelytoky and the number of reversions from obligate thelytoky to facultative and cyclic thelytoky are difficult to estimate. The other transitions are few in number: five origins of cyclic thelytoky, eight origins of obligate haplodiploidy (including paternal genome elimination), the strange case of Micromalthus, and the two reversions from haplodiploidy to diplodiploidy in scale insects. Available evidence tends to support W.D. Hamilton's hypothesis that maternally transmitted endosymbionts have been involved in the origins of haplodiploidy. Bizarre systems of extrazygotic inheritance in Sternorrhyncha are not easily accommodated into any existing classification of genetic systems^ref. Inclusive fitness theory has been very successful in predicting and explaining much of the observed variation in the reproductive characteristics of insect societies. For example, the theory correctly predicts sex-ratio biasing by workers in relation to the queen's mating frequency. However, within an insect society there are typically multiple reproductive optima, each corresponding to the interest of different individual(s) or parties of interest. When multiple optima occur, which party's interests prevail? Presumably, the interests of the party with the greatest 'power'; the ability to do or act^ref. In most species, however, workers can lay haploid eggs, which develop into males—nephews to the other workers and grandsons to the queen. Destruction of these eggs by other workers—and in some species by the queen—is usually sufficient to ensure that the vast majority of adult males are the queen's offspring. Worker policing in social insects has a more complex evolutionary basis than even their unusual patterns of genetic relatedness allow. Instead, it is the 'colony efficiency'—the cost that reproducing workers impose on the colony as a whole—that determines how many are tolerated^ref
2 male-specific olfactory receptors (ORs) in the silk moth, Bombyx mori, are mutually exclusively expressed in a pair of adjacent pheromone-sensitive neurons of male antennae: one that is specifically tuned to bombykol, the sex pheromone, and the other to bombykal, its oxidized form. Both pheromone ORs are co-expressed with an OR from the highly conserved insect OR subfamily. This co-expression promotes the functional expression of pheromone receptors, and confers ligand-stimulated non-selective cation channel activity. The same effects were also observed for general ORs. Both odorant and pheromone signaling pathways are mediated via a common mechanism in insects^ref.
Leaf-cutting ants live in obligate ectosymbiosis with clonal fungi that they rear for food. These symbionts are vertically transferred during colony foundation, but fungus gardens are, in principle, open for horizontal symbiont transmission later on. Fungal ectosymbionts prevent competing fungal strains from becoming established by ancient incompatibility mechanisms that have not been lost despite millions of years of domestication and single-strain rearing by ants^ref. These fungal incompatibility compounds travel through the ant gut to make the ant feces incompatible with unrelated strains of symbiont. Thus, the fungi manipulate the symbiosis to their own advantage at the expense of the ants' potential interest in a genetically more diverse agriculture.
To meet their need for nitrogen in the restricted foraging environment provided by their host plants, some arboreal ants deploy group ambush tactics in order to capture flying and jumping prey that might otherwise escape. The ant Allomerus decemarticulatus uses hair from the host plant's stem, which it cuts and binds together with a purpose-grown fungal mycelium, to build a spongy 'galleried' platform for trapping much larger insects. Ants beneath the platform reach through the holes and immobilize the prey, which is then stretched, transported and carved up by a swarm of nestmates. To our knowledge, the collective creation of a trap as a predatory strategy has not been described before in ants^ref.
Canopy-dwelling ants in the tropical forests of the Americas have adopted a neat way of averting disaster should they fall from their perch. They glide to safety, steering towards their home trunk rather than plummeting to the ground, where they might never see their nest-mates again. Worker ants of the species Cephalotes atratus can glide in a chosen direction if dislodged by the wind or larger animals. By making video recordings of plummeting ants in Panama, Costa Rica and Peru, the researchers showed that they fly backwards, abdomen first, using their oar-shaped hind legs to steer towards the tree^ref. The ants' acrobatics allow them to hit their home trunk with 85% accuracy, and be reunited with their fellows within 10 minutes. This is a useful skill for C. atratus, which lives in colonies that inhabit a single tree. The rainforest is flooded for half of the year, so if they fall there's no way back. And even if the ground is dry it's pretty hazardous for them, with predators and unfamiliar terrain. Other ants, such as the African army ant Dorylus, will drop from trees, but they always end up on the ground. The remarkable self-preservation instincts of C. atratus may be a product of their small colony sizes. "In small colonies we tend to think of individual workers as more valuable per capita. But before trying to explain their behaviour, it might be best to check that gliding actually does come naturally to the ants : I would like to see these drop tests done in the laboratory, where there are no winds. Although these are the first insects to be hailed as directional gliders, more will be discovered among the many thousands of insect species
In a bizarre war of the sexes, little fire ants have evolved a novel way to fight for their gender's genes. The sperm of the male ant appears to be able to destroy the female DNA within a fertilized egg, giving birth to a male that is a clone of its father. Meanwhile the female queens make clones of themselves to carry on the royal female line. The result is that both the males and females have their own, independent gene pools, leading some to speculate whether each gender ought to be technically classified as its own species. We could think of the males as a separate, parasitic species that uses host eggs for its own reproduction. Many insects, including most bees, wasps and ants, sexually reproduce in order to create both queens and sterile female workers. Males are created when a female egg goes unfertilized. Unlike humans, whose males require genetic input from a father, these male insects simply have less genetic material than the females. But when Fournier and his team were studying little fire ants (Wasmannia auropunctata) in French Guiana, they found something quite different. It is by chance that we discovered this extraordinary genetic system. The team had set out to investigate how colonies in human-disturbed areas, such as plantations or quarries, differ from those in undisturbed rain forests. But after collecting 34 nests and analyzing the genomes of the queens and workers, and the sperm of the males, an unusual pattern emerged. Although the sterile workers carried one maternal and one paternal set of chromosomes as expected, the queens carried only maternal genes and the males carried only paternal genes. There's no other genetic system that's quite like this. Little fire ant queens produce two types of eggs: one that carries the full complement of maternal genes and develops without fertilization into future clones of the queen, and a second group that carries only one set of chromosomes and is fertilized with sperm from a male. Of this latter group of eggs, most develop into sterile workers. In some of the fertilized eggs, however, the maternal genes are somehow destroyed, leaving the eggs to develop into male ant clones. Something similar is known to happen in some fish, amphibians and insects, in which the paternal genes can be eliminated from a developing egg. But it is unusual for maternal genes to be wiped out. The researchers don't know why this happens, but they speculate that it is the outcome of an extreme case of conflict between the sexes. It's a selfish strategy, initiated by females. Under this strategy, queens transmit 100% of their genome to future queens. Males must adapt or disappear, so they choose to thwart queens by eliminating the female genome in fertilized eggs. This illustrates the extraordinary imagination of nature - or of males - to counteract the female strategy. The system may also help the worker ants to maintain as high a genetic diversity as possible, speculates Normark, since their genes come from two pools that do not intermix from one generation to the next. This could help to counteract the negative genetic effects of inbreeding^ref.
Researchers have found an earthly cause for a phenomenon that Peruvian locals call 'devil's gardens' in the Amazonian rainforest. These gardens consist of just one type of tree (Duroia hirsuta). This is such an eerie and unusual sight in the otherwise diverse Amazon that locals presumed there to be a supernatural cause. The ants (Myrmelachista schumanni) live inside the trees' hollow stems, safe from predators and the environment. They kill all plants other than their host plant by injecting formic acid into the leaves. In this way, they help their host plant, and their own colony, to spread. Such gardens can hold > 300 trees and millions of ants, and can be hundreds of years old. It's amazing that the ants exert so much control over their environment. They create a single species stand of plants in one of the most diverse places on the planet. The ants do it through injecting a natural poison^ref. The researchers planted saplings of a common Amazonian cedar tree (Cedrela odorata) inside an ant-infested forest. When they kept the ants away, the cedar trees thrived. But when ants had access to the young trees, the cedars all shed leaves after about 5 days. It seems that the ants bite a hole in the leaves and deliver a droplet of formic acid from their abdomens. The plant's vascular system then spreads this acid throughout the entire plant. Within hours of the attack, brownish areas appear along the veins of its leaves. Formic acid is very common among ants: about 25% of the 15,000 ant species produce it. Many ants use it to defend themselves against animal or insect attack. But this is the first time that ants have been seen using it as a herbicide. The devil's garden relationship joins a growing list of partnerships between plants and ants. Some plants have evolved to grow food for resident ants, which protect their host in return. Other ants physically cut away at neighbouring vegetation to help their host plants spread. But how can an ant tell whether a plant is the same species as its host or different? Can the ants can kill mature trees as well as saplings ? How widespread devil's gardens are in the Amazon.
Ever think your spouse is turning you grey before your time? Well things are very different for a beetle being studied by Swedish evolutionary biologists. They have found that some male bean weevils can slow down the ageing process in their mates simply by having sex with them. Female weevils (Acanthoscelides obtectus) live longer when mated with males that have been bred to reproduce later in life, report researchers at Uppsala University. By supplying a cocktail of age-defying chemicals with their sperm, the males stop their mates dying off before they have had the chance to produce a large family. The males are promoting their own selfish interests by being the good guys in this case. It benefits males if their mates live longer. It's a surprising finding, because reproduction is generally thought to accelerate the ageing process. Castrated male mice, for example, live longer without the body-ravaging side effects of testosterone. Ensuring that your genetic legacy is preserved in future generations can be a costly, tiring business. In general, ageing is not thought to be subject to strong evolutionary forces, because old age sets in after offspring have already been produced and genes already passed on. Genes that leave you weak and frail at 70 are unlikely to be weeded out if you have kids at 30. But there are some situations where both reproduction and longevity are possible. The team studied weevils that had been raised in the lab to breed either early or late in life. The early-breeding strain was developed by giving weevils free access to the beans inside which their larvae must develop. A late-breeding strain was created by denying the weevils any beans until a mating pair had already been together for 10 days. After many generations, the bugs evolved to deal with these conditions. When males from these different strains were paired with normal females, the females that were mated with late-breeding males lived significantly longer: 18.7 days on average, compared with 17.9 for females matched with early breeders^ref. It is not yet clear exactly how the males are prolonging their mates' lives : probably there is a magic ingredient in their ejaculate that boosts the females' health and vigour. But insect ejaculates are a soup of proteins and peptides that are immensely complex. Whatever the mystery ingredient, the early breeders do not bother supplying it because they don't have to. Because the females reproduce straight away the male still gets to be a dad, even if his mate dies young. Several early-breeding insects will even shorten the lifespan of their mates in their competition to capture females. The male fruitfly Drosophila, for example, produces a protein in its semen that makes it more difficult for other males to fertilize the same female; this chemical also happens to be toxic^ref. This unfortunate side effect is an example of the more usual situation, where sex is a game of give and take. The lucky mates of late-breeding bean weevils, who get both a long life and good sex, are probably an unusual case.
Forget the taste of your meal, how does it sound? That's the question that termites ask themselves when chomping into wood. It seems that these insects choose what to eat according to the way each piece of wood vibrates in response to their gnashing jaws. The finding could lead to new approaches to controlling termite damage. The scientists examined the feeding behaviour of the drywood termite species Cryptotermes domesticus, which thrives in several continents. Close relatives in the Kalotermes termite genus wreak havoc on homes in Europe. Scientists know that C. domesticus prefers eating small rather than large pieces of wood in the wild, but they were mystified about exactly how the termites made this choice. So the Australian group recorded the sound generated as termites tunnelled into pinewood, a common building material. Almost all wood-eating pest termites find it very palatable... unfortunately. When termites chewed their way through a 20-mm-long wood block, the sound of their bites created a vibration of 7.2 kHz. Termites in a similar block that was 160 m long generated a slower vibration at 2.8 of, which would match a high F note from a xylophone. Given the choice, the termites showed a clear preference for the smaller block. They were even more attracted than normal to the 20-mm block when its usual 7.2-of sound was boosted in volume. In this case, the insects burrowed 4 times more into the shorter block than the longer, clearly preferring the sounds of a small block of wood. The discovery about termites' use of sound has excited the scientific community^ref. As surprising as the termite insight may seem, even people use sound to select food. Humans can appraise the quality or condition of food using vibratory cues: tapping a melon gives is a good indication of ripeness. So why do these termites prefer smaller blocks of wood? I think that drywood termites have evolved a preference for smaller pieces of wood because their greatest competitors are not interested in small pickings. A penchant for smaller wood, which is more easily transported from place to place, has also allowed these termites to spread easily. Other species and types of termites may well prefer larger pieces of wood : after all, humans tend to think that bigger is better, particularly when selecting among pieces of cake or chocolate
Web resources :
• Termite tutorial
• Protecting your home against termites
Tiny radar devices have revealed patterns in the meandering flights of butterflies: the looping dives are thought to help them to search for food or a home. What's more, the radar technology could help conservationists to find safe havens for the insects amid fragmented agricultural landscapes. Researchers attached radio transponders, each weighing just 12 milligrams, to butterflies and used them to track around 30 of the insects. You have to carefully remove the hairs from their back first with a wax with Sellotape. After checking that the transponders did not affect the butterflies' behaviour, they were released them into a field that was being scanned by radar. When a transponder receives a radar pulse, it sends out a characteristic reply signal that the researchers use to track the butterfly. Similar technology drives collision-warning systems on aircraft. The small tortoiseshell (Aglais urticae) and peacock varieties (Inachis io) showed 2 distinct flight patterns: straight movement, in which they zipped over the ground at more than 3 metres per second, and longer, slower passages in which they flew in loops. The butterflies also appeared to react to features as far as 200 m away, for example, by altering their course to investigate a group of flowers. Such patterns have been spotted before, although they have never been documented in the detail provided by the radar technique. Visual observations become difficult at distances of greater than 50 metres, but the Rothamsted team was able to follow the butterflies for > 1 km. The looping flight is thought to be a searching behaviour. The experiments were carried on in late summer, so the insects were probably looking for nectar from flowers, or a dry place, such as a crack in a tree, in which to hibernate. Straighter flights probably occur when the butterfly wants to leave an area or escape a predator. The experiment will be repeated on rarer species such as the high brown fritillary (Argynnis adippe) and marsh fritillary (Euphydryas aurinia). Both are endangered and conservationists are unsure how easily the insects will be able to move between neighbouring habitats that can support them. If we know how mobile they are, we can tell if the fragmentation is all right

Wolbachia is a common maternally inherited bacterial symbiont able to induce crossing sterilities known as cytoplasmic incompatibility (CI) in insects. Wolbachia-modified sperm are unable to complete fertilization of uninfected ova, but a rescue function allows infected eggs to develop normally. By providing a reproductive advantage to infected females, Wolbachia can rapidly invade uninfected populations, and this could provide a mechanism for driving transgenes through pest populations. CI can also occur between Wolbachia-infected populations and is usually associated with the presence of different Wolbachia strains. In the Culex pipiens mosquito group (including the filariasis vector C. quinquefasciatus) a very unusual degree of complexity of Wolbachia-induced crossing-types has been reported, with partial or complete CI that can be unidirectional or bidirectional, yet no Wolbachia strain variation was found. Variation between incompatible Culex strains in 2 Wolbachia ankyrin repeat-encoding genes associated with a prophage region, one of which is sex-specifically expressed in some strains, and also a direct effect of the host nuclear genome on CI rescue^ref
Researchers have found a tiny caterpillar in the rainforests of Maui, Hawaii, that weaves silk to tie up sleeping snails. Most caterpillars feed on plants, but Hyposmocoma molluscivora feasts on the flesh of living molluscs. The caterpillars, which grow up to be moths, perform this trick by camouflaging themselves in a purpose-built silk casing stippled with foliage and lichen. When it encounters a resting snail (Tornatellides), the caterpillar immobilizes it by binding it to leaves with silk threads comparable to those in a stiff spider web. "The larvae stretches from its case into the shell and pursues the snail until it is trapped^ref. It then eats the snail alive in its own house. They don't do this just to add spice to their diet. They have an inflexible digestive system that is unable to process other food types, a common trait in caterpillars. The caterpillar spends around 25 minutes weaving the silk trap, and takes all day to devour its meal. Out of > 150,000 types of moths and butterflies of the order Lepidoptera in the world, about 200 are predatory, and all of these are silk spinners. The real zinger here is that this is the only one that uses silk to capture prey. The others use their silk for more benign purposes, such as spinning coccoons. So far H. molluscivora have only been found in Hawaii. But on that isolated island archipelago they are quite widespread: researchers have found predatory caterpillars capturing and consuming snails on four of the five islands. The discovery provides evidence of the importance of isolation in the evolution of novel traits. A system like Hawaii, which doesn't have any social insects such as ants or wasps, is less diverse. But it is also more tolerant of evolutionary experiments or pathways. It also emphasizes the need to preserve unique ecosystems such as the Hawaiian rainforests
Taste sensation and food selection by animals can change adaptively in response to experience, for example to redress specific nutrient deficiencies. In 2 species of caterpillar, infection by lethal parasites alters the taste of specific phytochemicals for the larvae. Given that these compounds are toxic to the parasites and are found in plants eaten by the caterpillars, their changed taste may encourage parasitized caterpillars to increase consumption of plants that provide a biochemical defence against the invaders^ref.
The queen of a honeybee colony has a reproductive monopoly because her workers' ovaries are normally inactive and any eggs that they do lay are eaten by their fellow workers. But if a colony becomes queenless, the workers start to lay eggs, stop policing and rear a last batch of males before the colony finally dies out. Workers of the Asian dwarf red honeybee Apis florea from other colonies exploit this interval as an opportunity to move in and lay their own eggs while no policing is in force. Such parasitism of queenless colonies does not occur in the western honeybee A. mellifera and may be facilitated by the accessibility of A. florea nests, which are built out in the open^ref.
Water-walking insects and spiders rely on surface tension for static weight support and use a variety of means to propel themselves along the surface. To pass from the water surface to land, they must contend with the slippery slopes of the menisci that border the water's edge. The ability to climb menisci is a skill exploited by water-walking insects as they seek land in order to lay eggs or avoid predators; moreover, it was a necessary adaptation for their ancestors as they evolved from terrestrials to live exclusively on the water surface. Many millimetre-scale water-walking insects are unable to climb menisci using their traditional means of propulsion. Through a combined experimental and theoretical study, here we investigate the meniscus-climbing technique that such insects use. By assuming a fixed body posture, they deform the water surface in order to generate capillary forces: they thus propel themselves laterally without moving their appendages. A theoretical model has been developed for this novel mode of propulsion and use it to rationalize the climbers' characteristic body postures and predict climbing trajectories consistent with those reported here and elsewhere^ref
The ant Temnothorax albipennis uses a technique known as tandem running to lead another ant from the nest to food —with signals between the two ants controlling both the speed and course of the run. Tandem running is an example of teaching, to our knowledge the first in a non-human animal that involves bidirectional feedback between teacher and pupil. This behaviour indicates that it could be the value of information, rather than the constraint of brain size, that has influenced the evolution of teaching^ref.
A conundrum about the chemical make-up of fossilized insects has been solved this week by scientists who baked up scorpions to find the answer. Modern arthropods, including cockroaches, scorpions, beetles and shrimps, have shells made up of chitin. Chitin consists of stringy carbohydrate fibres rather like plant cellulose that are embedded in a hard protein matrix, with a waxy layer on top. But their fossilized counterparts have an entirely different chemical make-up. Fossils surviving from 30 million years ago have an outside skeleton containing 'aliphatic' molecules with long chains of carbon atoms, very similar in structure to the chemical compound kerogen, a precursor to components of petrol. How do you go from chitin, the carbohydrate, to these long-chain hydrocarbon precursors? Fossil fuels are made over long time periods when carbon-based material is compressed deep within the Earth. Kerogens are a stage in the process to fossil fuels. There are several different types, and there's an ongoing debate about how they form. For marine algae, kerogen is formed by 'selective preservation', as long-chain molecules already in the algae resist decay. Many assumed the same was true for arthropods and other carbon-based material. Perhaps small quantities of aliphatic molecules in insects are preserved over millions of years while the chitin is lost. But no aliphatic molecules have been found in modern insects. Alternatively, perhaps some outside source provided the hydrocarbons, or maybe waxes on top of the chitin somehow combined to produce them. To answer the question, the scientists decided to make their own artificial fossils from modern arthropods. They obtained live emperor scorpions, shrimps and Madagascan hissing cockroaches from Bristol Zoo, and froze them to death. The outside skeleton was removed and baked at 350 °C at around 700 atmospheres pressure for a day in sealed gold containers. This is an established process that roughly mimics the way fossils form over millions of years, compressed into a single day by upping the temperature. The team analysed the resulting 'fossilized' arthropods, and found new aliphatic compounds that hadn't been there before the treatment^ref. But chitin extracted from the skeleton, when baked on its own, did not produce these compounds. Nor did bits of skeleton that had their waxy layer removed. The conclusion: the waxy 'lipid' layer on the outside of the skeleton and in some of its internal tissues is responsible. Though we still don't know exactly how. The researchers are now applying their technique to fossilized plants as well, to work out the intimate details of how fossil fuels can be made from material such as decaying leaves
See also : insect immune system and diseases of insects
Web resources :
• Insect, Disease and History site by Dr.Robert Peterson
• The Virtual Library - Entomology
• Usenet sci.bio.entomology
• Antbase
• Nomina Insecta Nearctica
• Coleoptera
• Collembola
• Diptera (Australasian and Oceanian)
• Drosophilidae
• Formicidae (AMNH ants).
• Fulgoromorpha Lists On the WEB
• Hymenoptera 1 and 2
• Cyberbee : honey bees
• Drosophila Melanogaster (fruit fly)
• Flybase : Drosophila melanogaster genome and anatomy
• Flybrain : Drosophila melanogaster brain and nervous system
• Ichneumonidae
• Isoptera 1 and 2
• Lepidoptera 1 and 2
• Mecoptera
• Nearctic Spider Database
• Odonata 1 and 2
• Orthoptera
• Trichoptera
• Social insect page
• The Amphipod Homepage
• Smithsonian world list of aquatic and terrestrial Isopoda
• Scorpiones 1 and 2
• Cladocera
• The World Spider Catalog
• Invasive and Exotic Species of North America
Bibliography : Parasite Rex : Inside the Bizarre World of Nature's Most Dangerous Creatures by Carl Zimmer
• Fishes


A crucial fossil that shows how animals crawled out from the water, evolving from fish into land-loving animals, has been found in Canada. The creature lived some 375 million years ago. Palaeontologists are calling the specimen from the Devonian a true 'missing link', as it helps to fill in a gap in our understanding of how fish developed legs for land mobility, before eventually evolving into modern animals including mankind. Several samples of the fish-like tetrapod, named Tiktaalik roseae, were discovered by Edward Daeschler of the Academy of Natural Sciences in Philadelphia, Pennsylvania, Neil Shubin of the University of Chicago in Illinois, Farish Jenkins of Harvard University in Cambridge, Massachusetts and colleagues. The crew found the samples in a river delta on Ellesmere Island in Arctic Canada; these included a near-complete front half of a fossilized skeleton of a crocodile-like creature, whose skull is some 20 cm long. The beast has bony scales and fins, but the front fins are on their way to becoming limbs; they have the internal skeletal structure of an arm, including elbows and wrists, but with fins instead of clear fingers. The team is still looking for more complete specimens to get a better picture of hind part of the animal. Creatures with features of both fish and land-living animals have been found before. Fish that may have been beginning to 'walk' in shallow water have been found from about 385 million years ago, and fish with limbs that bear digits have been seen from more than 365 million years ago. Specimens that fall into the gap, such as Tiktaalik, help researchers to work out the details of this transition. The newly found animal has a structure on its head that looks like a small gill slit that is on its way to becoming an ear, for example, and a long snout that would have been suited to catching prey on land. Tiktaalik substantially narrows the gap in the fossil record of the fish-tetrapod transition. Tiktaalik was probably an unwieldy swimmer. It probably lived in shallow waters, says Maisey, only hauling itself on to land temporarily to escape predators. Tetrapods did not so much conquer the land, as escape from the water. Daeschler and Shubin set off to find this missing link in the evolutionary chain back in 1999. The pair targeted Ellesmere Island after noticing that it was listed in an undergraduate textbook as exposed Devonian rock that had not previously been explored for vertebrate fossils. The desolate area was reachable only by plane, and the weather was so bad that field work could only be done for about two months each summer. The team first walked around the rocky outcrops looking for fossils of plant life that indicated stream or delta sediments, in order to target areas that had once hosted shallow waters. That is where the action is on the fish-to-tetrapod transition. By 2000 they had found fossils with intriguing fins in the eroding rocks. In 2004, we really scored, finding three partial skulls and numerous jaws^{ref1, ref2}

Sounds made by a deep-water fish have been encountered for the very first time. Although the identity of this voluble creature remains a mystery, scientists believe it uses its call to find mates in the dark ocean depths. Shallow-water fish such as croakers and toad-fish are known to make a limited range of sounds, but deep-water fish, which are those that live far from continental shelves at depths > 500 m, have not been heard before. The sounds were recorded by four underwater microphones (hydrophones) at the bottom of the ocean between the Bahamas and the coast of Florida. The listening posts are owned by the US Navy's Atlantic Undersea Test and Evaluation Center, which normally listens for approaching submarines, which was tracking sperm whales with the hydrophones to work out how the creatures respond to artificial sounds in the ocean. She heard some unusual croaking sounds from about 600 m below the surface^ref. She estimates that the fish is < 20 cm long. Larger fish tend to sing baritone, and the mystery creature is an alto. Marine biologists have speculated that some deep-sea fish could produce sounds by rubbing specialized muscles along ridges on their swim bladder, like dragging a stick along iron railings. The new sound fits that theory. The possibility that a whale could be making the noise has been ruled out. One recording followed the fish for about half an hour as it dived from 550 m to 700 m. A whale would have had to surface in that time. Furthermore, whales use high-pitched sounds for echolocation and lower notes for communication; and recordings sit in the middle range of the oceanic orchestra, which is normally dominated by fish. The sound is almost certainly a mating call because this is the most likely reason for the fish to risk giving away its position to potential predators. There is no light down there, so it is absolutely logical that they make sounds to attract a mate. The fish are quite rare, as many have failed to find similar calls in hydrophone recordings from other parts of the world. Since the sounds could be heard > 4 km away, the fish may have very few potential mates. These recordings are the first step to learning more about how the fish reproduces. Deep-sea fish like the blue grenadier (Macruronus novaezelandiae) are now being fished aggressively, which may threaten many species that live in the same areas of the ocean. These fish are often very long-lived, very slow to reproduce, and very easy to wipe out, especially when we know nothing about the population in the first place. Researchers now hope to use an underwater vehicle to identify and track the sound, in order to get photographs of the creature.
Swordfish (Xiphias gladius) keep their eyes warm while the rest of the body remains resolutely cold-blooded: it's all the better to see their prey with. Heat-assisted eyes work more than 10 times faster than those cooled to the coldest deep-sea temperatures of around 3 ºC. This increased 'temporal resolution' helps swordfish to catch dinner in the inky depths. Researchers already knew that swordfish can selectively warm their eyes and brains. The fish have a specially adapted heating organ in the muscle next to their tennis-ball-sized eyes, which can raise temperatures in the surrounding tissue some 10-15 ºC above that of the water in which the fish is swimming. But heating takes a lot of energy, and until now experts were confused as to why the swordfish goes to the trouble. Heat is lost around 3,000 times more quickly to water than to air, and of the 25,000 or so species of bony fish, only 22 - including swordfish, marlin, tuna and some sharks - have been found to possess any kind of heating mechanism. Evaluating the benefits of swordfishes' warm eyes has been difficult because the fish live in the remote open ocean : researchers took retinas from the fish and, over a range of temperatures, tested the speed at which the membranes could distinguish movement by measuring the 'flicker fusion frequency'. This is the point at which a flickering light becomes too rapid for the retina to generate separate nerve impulses for each individual flash. The swordfish retinas' performance improved greatly as the temperature rose. Retinas from the warm-blooded tuna also improved with temperature but only by about half as much, perhaps reflecting the fact that their whole-body heating has evolved for its general advantages in areas such as locomotion, not just vision. The heater allows swordfish to capture valuable light more quickly, helping them to catch sight of speedy prey such as squid. So the fish have developed a way to capture the light more quickly, effectively giving them a faster 'shutter speed'. The theory is boosted by the fact that swordfish live at temperate latitudes in which sea temperatures drop swiftly with increasing depth. Eye heaters allow them to delve deep in the water in search of a meal. The researchers' results stop several degrees short of the 28 ºC to which the fish have been known to heat their eyes in the wild. Swordfish eyes should be compared with those of completely cold-blooded fish of a similar size, and to those of the butterfly mackerel, a fish from the tuna family that specifically warms its eyes, although it uses a different mechanism
Mimicry in vertebrates is usually a permanent state — mimics resemble and normally accompany their model throughout the life stages during which they act as mimics. The bluestriped fangblenny fish (Plagiotremus rhinorhynchos), which aggressively attacks other coral-reef fish, can turn off the mimetic colours that disguise it as the benign bluestreak cleaner wrasse, Labroides dimidiatus, and assume a radically different appearance. This opportunistic facultative mimicry extends the fangblenny's scope by allowing it to blend into shoals of small reef fish as well as to remain inconspicuous at cleaning stations^ref. Sexual mimicry among animals is widespread, but does it impart a fertilization advantage in the widely accepted 'sneak–guard' model of sperm competition? Single males can adopt a sophisticated feminine disguise to help them get near females that are guarded by large males. Now researchers have proved that the mimics, who can change their appearance instantaneously, are successfully mating with such females. Each year, during the winter, thousands of giant Australian cuttlefish (Sepia apama) gather on the southern coast of the continent to mate. The competition between males for the females is intense. On average, 4 males fight over each female, but the ratio can be as high as 11 to 1. The winner of each challenge, usually a large male, guards his mate closely. But smaller males still manage to secure about 33% of all matings. There is a range of tactics from which a 'sneaker' male can choose. The options include waiting until the consort male is busy fending off a challenge; meeting his mate under a rock as she prepares to lay an egg; and disguising oneself as an female. The latter approach is an "elaborate trickery". To be convincing, the mimic has to take on a mottled colouring, hide some of his arms and alter the shape of the visible ones. Although the practice has been seen before, until now no one had proved that it works, that is, that the sneaker males actually manage to fertilize the target females. In 30 out of 62 attempts, 5 female mimics deceived the guard male and got close to females. The researchers used DNA fingerprinting to show that 2 of the mimics succeeded in making a female pregnant. These results are surprising, given the high rate at which females reject copulation attempts by males, the strong mate-guarding behaviour of consort males, and the high level of sperm competition in this complex mating system. Cuttlefish may be the most talented quick-change artists in the animal kingdom. The team also found that the mimics could change their appearance as fast as 10 times in 15 minutes^ref. Sexual mimicry is not new to the animal world. Both bluegill sunfish (Lepomis macrochirus) and red-sided garter snakes (Thamnophis sirtalis parietalis) are known to make use of it, for example. But male cuttlefish are the only animals known that can turn the change in physical appearance on and off so quickly.
A lobster's colour is due to a pigment molecule called astaxanthin, which is attached to a protein called crustacyanin. Astaxanthin is one of the carotenoid pigments responsible for the bright red colours of many animals and plants, including those of oranges, tomatoes and some birds' feathers. When a lobster is boiled, its crustacyanin proteins unwind in the heat and the astaxanthin pigment falls off. This 'free' astaxanthin is red, just like most other carotenoids, and gives the lobster its freshly-cooked colour. When astaxanthin is embedded in the crustacyanin molecule to change its colour^ref, red pigments absorb blue and green light and reflect the red part of the spectrum. When astaxanthin is incorporated in crustacyanin, its absorption is shifted across the spectrum towards longer (redder) wavelengths. This means it absorbs all visible light, so the pigment appears black. One idea, discussed for many years, is that the molecular scaffolding of the crustacyanin molecule distorts the shape of the astaxanthin, allowing it to absorb light across the spectrum. This would be rather like altering the resonant frequency of a piano wire by making it shorter or tighter. But the pigment's quantum energy states, which show that merely changing its shape accounts for only about a third of the shift in absorption wavelength. This alone cannot make the pigment turn from red to black. Another proposal is that the pigment becomes electrically charged inside the protein, but NMR rules this out. Instead, the team followed up on the discovery in 2002 that astaxanthin molecules in the crustacyanin proteins are grouped in pairs that cross each other in an X-shape^ref. This pairing, the researchers' calculations show, means that the two molecules interfere with one another, like cross-talk between electrical signals in neighbouring wires, and this shifts their quantum energy states. That in turn alters the wavelength of light that they absorb, accounting for most of the blackness.
Teleost fishes maintain buoyancy using a gas-inflated swimbladder. Oxygen is pumped into the swimbladder by means of a complex arrangement of veins and arteries, known as the rete mirabile, and special pH sensitive "root-effect" hemoglobins, which also have low specific buffer values. A Na⁺/H⁺ exchanger regulates the intracellular pH of red blood cells. Many fish also have an ocular rete mirabile to support the high metabolic activity of the avascular fish retina. Root-effect hemoglobins must have appeared before the rete mirabile. The ocular retia--which required the presence of the Na⁺/H⁺ exchanger--likely evolved 100 million years before the swimbladder retia, whose appearance correlates with significant adaptive radiation in teleost fish^ref.
The longest ever attempt to keep a great white shark in captivity has come to an end. After 6 months, officials at Monterey Bay Aquarium in California were forced to release the female shark as she lived up to her reputation and began killing her tank-mates. Aquarium staff returned the shark to the Pacific Ocean near Point Pinos, California, on 31 March 2005, marking an end to her 198-day stay. She was accidentally caught in a fisherman's net off southern California in September 2004. But researchers at the aquarium aren't yet finished with the shark. She is equipped with a tag containing instruments to measure her whereabouts, depth of dives and preferred water temperature. After 30 days the tag will release itself and float to the surface, where it will transmit its findings to a satellite. Besides allowing marine scientists a close and personal view of a great white (Carcharodon carcharias), the 70-kg shark has boosted the aquarium's fortunes. Public attendance at the tourist attraction surged by almost one-third after her arrival. But her aggressive behaviour ultimately led to the decision to remove her from the tank she shared with several other sharks and fish. There was a clear sense she was hunting other animals : not least among these were 2 soupfin sharks who died as a result of her attacks, although aquarium officials maintain that other species with which she was housed remained safe. Experts at California's Pelagic Shark Research Foundation had previously argued that aggression towards other sharks was a sign that she did not have enough room to roam. The great white's nose was damaged by rubbing the tank walls during her captivity, perhaps another sign of stress. The aquarium's veterinarian found no infection at the site of the wound, however: her overall health was excellent, as are her prospects for survival in the wild. The aquarium remains keen to study great whites, and has pledged to try to obtain another one for further study. They hope to bring another to Monterey so we can continue to change public attitudes about this feared and much-maligned ocean predator.
After months roaming the waves as larvae, it seems that fish tune into the sounds of home when they want to settle down. A study on Australia's Great Barrier Reef has shown that the crackle of shrimp and the calls of fellow fish serve to attract tropical tiddlers. Researchers working near Lizard Island, 240 kilometres north of Cairns, Queensland, set up 24 fake reefs made from dead coral. 50% of the reefs contained submersible speakers that played a cacophony of genuine reef noise consisting of snapping shrimp and other fish. Noisy reefs attracted a far greater number of fish than those that were silent. We knew that they were attracted to light traps, but no one had shown that the fish located sound and could be encouraged to settle depending on it. Around 80% of the fish attracted to the reefs were cardinalfish (apogonids), and most of the remainder were damselfish (pomacentrids). But noisy reefs also attracted a wide range of less common fish. Sound could be a key tool for developing or restocking fisheries. Commercial divers gathering tropical fish often use cyanide, which destroys coral. A 'pied piper' approach to collecting or moving fish would be preferable. However, collecting fish indiscriminately may affect the stability of the reef as a whole. You have to be very careful with interpreting these results. These are experimental tests in a restricted system. The total number of fish out there is going to stay the same, wherever you move them. Collecting very young fish could aid conservation efforts: reef fish typically have a mortality rate of 70% in the first 2 to 3 days of juvenile life. The Straits of Hormuz in the Gulf carry 25% of the world's oil shipments and researchers are investigating whether fish are attracted to or repelled from certain places by tanker noise^ref.
In what could explain earlier findings that just a small number of genetic changes control the widespread evolution of many species of sticklebacks, mutations in a single gene appear to be responsible for the changes in the armor of these widespread fish. Reductions in the armor of 3-spine sticklebacks that have migrated from marine water to freshwater is an example of parallel evolution derived from an allele on a single gene, Eda. While the morphological change is large, the underlying genetics are simple. Marine water fish carry the genetic change at such a low frequency that individual animals do not carry homozygous alleles for the gene, a condition required for the development of low-plated fish. But when these marine fish move to a new freshwater environment, the low-plated phenotype has a selected advantage, and the low-plated fish can appear quickly through natural selection at a higher frequency of the preexisting genetic change. Eda encodes the signaling molecule ectodermal dysplasin, which controls the development of hair and teeth in human embryos and the bony plate armor of sticklebacks. Sequencing and comparing the complete Eda region in marine and freshwater fish revealed that most low-plated populations in the wild shared the same base pair changes. Sequence amplification from 25 random nuclear genes failed to show evidence for one single origin of low-plated sticklebacks. To confirm that different levels of Eda signaling could change plate development in these fish, the researchers injected one-celled embryos from low-plate parents with a full-length mouse Eda A1 cDNA. When used in mice carrying a null mutation at the Eda locus, this construct has been shown to restore development of teeth and hair. PCR genotyping of the fish in this cross confirmed that they were all homozygous for the low-plate Eda allele. Due to mosaic inheritance of the gene, some transgenic animals developed extra plates, but none of the controls did. It is a good example of selective polymorphism, which is hidden in the marine population : as soon as the fish go into fresh water, there is strong selection for the allele. In addition to identifying the gene responsible for the change in stickleback plate armor, this study makes another important point about parallel evolution. Rather than using hundreds of ways to solve a problem, evolution uses a particular mechanism repeatedly to solve a problem. It would be interesting to know how often this kind of single gene activity happens in other plants and animals. While Eda is a gene of major effect, but natural selection usually occurs in situations of multiple genes with smaller effects, so it would be interesting to look at this more common situation in natural selection.
Web resources :
• Marine Biological Laboratory
• University of Maine Lobster Institute
Deep-sea fish are suckers for lures lit up in red, challenging a long-held belief of marine biologists. They claim that a deep-sea relative of jellyfish uses glowing tentacles to catch its supper. Using a remotely operated submersible, up to 2,300 m beneath the waves off the coast of California, 3 specimens of a new species of siphonophore, a group closely related to jellyfish and corals, were collected. 2 of the 3 had the remains of fish in their guts. As fish are rare at those depths, this indicates that the species (which has not yet been named but is part of the genus Erenna) has a knack for angling. The siphonophore uses red light as bait to capture its prey. The newly described species has glowing red spots inside its stinging tentacles (bioluminescence), which it flicks rhythmically. The motion and shape of the lures is quite distinct and nearly identical to that of a copepod, suggesting that the siphonophore mimics the movements of plankton to catch the attention of fish. To us, the accumulated evidence is hard to explain any other way. But this explanation is controversial, because red light doesn't travel very far through water, and most biologists think that deep-sea creatures are adapted to see blue light rather than red. Of the 2,000 to 3,000 known species of deep-sea fish, we have looked at the visual pigments of around 250. Only 3 species are sensitive to red light. If this is a lure, it would have to be specific to these three species of fish. Haddock couldn't identify the fish in the guts of his siphonophores, so he doesn't know if they are of species known to be able to see red. But the siphonophores wouldn't have developed the lures unless they could attract a good proportion of fish. Perhaps red vision is more common than assumed. Deep-sea fish caught by researchers are now often sorted on deck under red light, in an attempt to preserve their visual apparatuses for study. Ironically, this would destroy any red-sensitive visual pigments. In challenging the 'conventional wisdom' we are not saying that blue-vision is not the dominant mode of operation, just that there is evidence for red light being used. Douglas suggests that the siphonophores might be using their lures for something other than fishing. It's at least as likely that they are using them for signalling to one another, although he has little idea what siphonophores might have to talk about^{ref1, ref2}
A strange kind of humming fish has evolved a clever way to avoid deafening itself with its own noise, researchers have found. The same mechanism could be at work in other animals, including humans, helping to tone down the senses and avoid overpowering them with self-generated signals. The male plainfin midshipman fish (Porichthys notatus) is a 25-cm-long fish that lives off the west coast of the USA from California to Alaska. During summer nights, they hum to attract females and encourage them to lay their eggs. The hum, described by some as similar to the chanting of monks, is so loud that houseboat owners near San Francisco have sometimes complained of their homes vibrating at night. Bass and his fellow authors have shown that the brains of these fish regulate their hearing so that they are not deafened and can hear predators or incoming females even while humming. The fish control both sound and hearing through nerve impulses from the same part of the brain. Some impulses signal to muscles around the swim bladder, which is the fish's buoyancy organ, making it generate sound by vibrating. The same area of the brain sends signals to inhibit the sensitivity of the ear's hair cells, which translate sound into electrical signals that the brain can understand. When the researchers looked at these signals in detail, they found that both happened about 100 times per second. They were also perfectly coordinated so that the bladder vibrated at the exact same time that the ear's sensitivity was reduced. The ears weren't simply tuning out in response to a loud blast of noise: they paralysed the fish to silence their hums, and found that the two signals were still synchronized^ref. Studies in crickets, bats, monkeys and even humans have shown that hearing can become less sensitive during sound production. But it has not been clear how this happens. The team notes that all vertebrates have a nerve connection between the brain and ear that is similar to that found in the plainfin midshipman, so it is probable that they all use the same mechanism to adjust their hearing. Without a doubt humans use this principle. Humans might use the same mechanism for other senses, including touch and smell. You never smell yourself, but someone else might. Humans have a second mechanism to protect their ears when exposed to loud noise: a reflex tightens muscles in the inner ear to stiffen the eardrum and inner ear bones so they become less efficient at transmitting sound. But this response gets weaker with repeated exposure to noise, and can only protect us from short-lived sounds. It also cannot protect us from noises that reach the ear through the bones in the head. The mechanism identified in the humming fish can. If the same process happens in humans, it might play an important role in how we recognize our own voice. This could have important implications in learning to speak^ref
Japanese researchers snapped a 8-metre giant squid as it attacked their bait in the inky blackness almost 1 km below the waves. The giant squid, Architeuthis, is the largest invertebrate in the world. > 580 individuals have been washed up on shorelines since the 16th century, giving marine biologists a good idea of their size and lifestyle. Some of the specimens have reached 18 m in length, including tentacles, and weighed almost a tonne. The animals are thought to be rare and live only at great depths, so living specimens have remained elusive. The photographs were taken by zoologist Tsunemi Kubodera of the National Science Museum, and Kyoichi Mori of the Ogasawara Whale Watching Association, both based in Tokyo. They used a 1,000-m baited fishing line with a camera attached to record the close encounter in the deep. Their images show a giant squid aggressively engulfing the bait at a depth of some 900 m. During the encounter, which lasted > 4 hours, the squid became entangled in the apparatus and eventually beat a retreat, leaving behind a 5.5-m section of one of its feeding tentacles. The tentacles are covered with suckers, as Kubodera and Mori discovered when they hauled the segment on board and found that it could still grip their fingers. They confirmed the creature's identity by taking DNA samples from the tentacle and comparing them with those of previously collected giant squid specimens^ref. The snapshots also show that giant squid are more active predators than previously thought. The long tentacles are clearly not weak fishing lines. The squid wrapped its arms around the bait much as a python wraps itself around prey. Captured near Chichijima Island in the North Pacific, the pictures come after years of a frustrating, international quest to photograph the creatures. Previous attempts have involved remote-controlled observation submarines, and cameras have even been strapped to sperm whales, which are known to feed on giant squid. Kubodera and Mori chose the region because sperm whales regularly gather there in the autumn to make deep feeding dives. The undersea landscape near Chichijima has steep, creviced rock faces that are thought to make a cosy home for squid. After nearly three seasons and 23 deployments of the lure, this choice location finally yielded the lucky catch. Despite these insights, we don't fully understand the mysterious lifestyle of the giant squid. Researchers are still trying to determine, for example, whether human exploration of the sea floor using high-intensity sound pulses threatens the squid by forcing them upwards into warmer waters that may kill them. The difficulty of spotting giant squid in their natural habitat makes these questions hard to answer. There is still much to learn about these spectacular animals.
Abandoned deep-sea fishing nets are killing large numbers of fish and sharks in the northeast Atlantic. The warning comes from a joint project between Britain, Norway and Ireland that is examining the largely unregulated fishing in that area, called DEEPNET. The situation may warrant emergency measures that would close the fishery for 6 months while an improved management policy is put in place. Up to 50 vessels have been operating in deep-water fisheries to the west and north of Great Britain and Ireland since the mid-1990s. These ships drop their nets into the deep waters of the Atlantic for 3-10 days at a time. This efficiently picks up a large number of fish, but the process is wasteful: about half of the catch is unfit for human consumption by the time the nets are retrieved. On top of this, the ships often lose or abandon their nets, which can be up to 250 km long. This produces death traps on the bottom of the sea that continue to catch and kill fish and sharks. There is no monitoring of what these vessels are fishing. This has been going on since the 1990s and there are literally no data on this fishery; it is as if it doesn't exist. The project was set up on March 2005 to collect data and draw international attention to the problem. Scientists with the Centre for Environment Fisheries and Aquaculture Science (CEFAS), which works for the UK government, are starting a more extensive, 20-day survey in Sep 2005. Their conclusions, to be released at the end of October, may help to prompt new regulations. Researchers from DEEPNET ran a net-retrieval operation in August 2005. Discardment is a big deal. Huge amounts of gear basically abandoned were found. Some of the nets they found had been left there 8-9 months. Because there is little current the nets don't get tangled. Instead they fill, the fish degrade and the net empties and then fills up again. The deep-water species targeted by these nets include the leafscale gulper shark (Centrophorus squamosus), which is particularly vulnerable to population loss because of its slow reproductive rate, and the Portuguese dogfish shark (Centroscymnus coelolepis). Other species of fish and shark are caught as by-catch, including rays, ling and deepwater red crab. Current European regulations focus on the size of the nets and the allowable catch. But there are no restrictions on how long the nets can soak in deep waters, or how many fish can be discarded from the nets. There are 2 broad types of control, one which limits fishing effort and one for total allowable catches for some species. Britain campaigned for stricter regulations during discussions with European Union member states when formulating these rules in 2002.  The problem with monitoring the vessels is time and money. The vessels are often out for 50-100 days at a time, making it hard to install observers on boats.  The fisheries department is currently working with DEEPNET to determine the full extent of the problem. They have asked the European fisheries commission to put forward a proposal on how to tackle the issue.
It turns out that even for a fish, eavesdropping might help in figuring out who you can trust not to stab you in the back. The sea bream Scolopsis bilineatus apparently spies on cleaner fish Labroides dimidiatus before deciding which of them to employ. Cleaner fish help out their larger 'clients' by eating parasites, for which they gain protection — although their preferred diet is the more nutritious mucous coating of the bigger fish. 'Cheating' behaviour, in which cleaners tuck into the mucous not the parasites, is rare, prompting biologists to wonder why. A series of experiments was set up to work out why the two species seem to get along so well instead of turning on one another. It seems that by feeding on parasites, instead of their preferred mucus, while other clients watch them at work, the cleaner fish build a reputation that stands them in good stead. Bshary and Grutter placed a client fish in the centre of an aquarium divided by two partitions. From here it could watch 2 cleaners, one at either end of the tank, through a two-way mirror. This way, the client could observe the cleaners without the cleaners being aware of it. One of the cleaners appeared to cooperatively interact with a model client fish that had had prawn, the cleaner fish's preferred food, smeared on it. The other cleaner fish swam randomly around its prawn-free model. Having observed the two cleaners, the client fish chose to spend significantly more time with the more reputable and seemingly helpful cleaner^ref. The client fish pay attention to what the cleaners are doing. In a second experiment, an artificial pulley system attached to a series of plates offering food to the cleaner fish. On one set of plates were prawns whereas the other plate held less appetizing food flakes. As soon as the cleaner fish fed on prawn was set up, the system would automatically remove both plates. Eventually the cleaner fish learned to eat the flakes even though both plates were offered. This shows that the cleaners are prepared to settle for second best in order to ensure a reliable food supply. They are willing to feed against their preference. Both experiments show that a state of mutualism can exist between the 2 fish. The cleaners feed on their second-choice diet to reduce conflict with their current client fish and build a reputation that allows future employment by other picky clients. Such 'image-building behaviour' is a well-known facet of human behaviour. Military generals, for instance, often base their tactics at least partly on what intelligence they perceive the other side to have, based on monitoring their enemy's behaviour. But seeing such sophisticated behaviour in animals such as fish is a surprise. That level of strategy behaviour across species is remarkable : the find is a major advance in the study of evolution of social behaviour. Other animals might also unconsciously manipulate their perceived image in this way, regardless of how 'smart' they are. Hormones, rather than conscious choice, help to dictate the fishy cooperation
See also diseases of fishes
Web resources :
• Atlantic Undersea Test and Evaluation Center (AUTEC)
• The Virtual Library - Fish
• Endangered Sharks
• FishBase
• Fish in the Bahamas
• Fish online
• Usenet sci.bio.fisheries
• World Fish Database
• Catalog of Fishes on-line
• Fish Information Service
• Guide to South American Cichlids
• Amphibia
• gray crescent : an area on some amphibian eggs from which pigment retreats; it is dorsal and opposite to the point of sperm entry, giving the first visible sign of the dorsoventral axis.
• Todd bodies : eosinophilic structures formed in the cytoplasm of the red cells of certain amphibians
• Ecker's plug : a plug of cells in the primordial mouth of the gastrula
• yolk plug : the mass of yolk cells protruding from the blastopore of amphibians at the end of gastrulation.
• common water striders (Aquarius remigis, a.k.a. Gerris remigis) have remarkable non-wetting legs that enable them to stand effortlessly and move quickly on water, a feature believed to be due to a surface-tension effect caused by secreted wax. However, that it is the special hierarchical structure of the legs, which are covered by large numbers of oriented tiny hairs (microsetae) with fine nanogrooves, that is more important in inducing this water resistance^ref.
• a mystery of exploding toads has turned many people into armchair zoologists this week. Amphibians in a previously obscure German pond have reportedly been blowing up in their thousands, leaving a grisly trail of innards stretching several feet in their wake - and observers desperately trying to work out why. The list of suspected culprits has grown to include bacteria, fungi, ozone and vehicle exhausts; or simply the pecking of hungry birds. In the wake of the confusion, reports have also emerged of toads meeting a similarly gruesome fate in Denmark. Despite much puzzling, experts have yet to find any reason for the amphibians to balloon to 3 times their size before literally exploding, as eyewitnesses to the unfortunate incidents have claimed. Various theories independently explaining observations of bloated toads and messy remains lead many biologists to think that observers have been leaping to conclusions, and that the toads are not really exploding. The toads first came to prominence when walkers noticed an unusually large number of corpses splattered on the ground near what has now been dubbed the 'Pond of Death'. The current body count in Hamburg has reached some 1,300. Experts, having sampled the pond water, say they have ruled out the possibility of a killer pathogen. The water from the pond and from the nearby River Elbe contains no pathogen or pesticide that is known to be lethal to wildlife. And when Himmelreich and her colleagues carried out a biotest on the water (they put fish and shrimps in to see if they could survive) it came out clean. Some of the corpses bear the scars of a predator's attack : birds may simply have made a very messy job of eating their favourite parts of the toads, such as the liver. April and May are the months when toads migrate to ponds to spawn, which means that this season could represent easy pickings for birds. Perhaps the walkers let their imaginations run wild when they chanced upon the victims, she proposes. There are some symptoms that might lead an observer to think that a toad was on the verge of blowing up, particularly if a wounded toad wandered into a pond. Maybe they were full of water, and in their agony they were also trying to suck in air. People watching bloated, rasping toads might well think an explosion was imminent. Some toads are also known to puff themselves up as a defence reaction, perhaps as a means of warding off attack by snakes aiming to swallow them whole. But zoologists doubt that a toad could swell to 3 times its usual size
Web resources :
• Amphibians of the World (on-line version):
• Amphibiaweb
• Xenopus laevis (frog)
• Frog calls : declining amphibian populations by Prof.Tim Halliday
• Aesop's fable - The Frog and the Ox
• Reptiles

Oxygen consumption by carnivorous reptiles increases enormously after they have eaten a large meal in order to meet metabolic demands, and this places an extra load on the cardiovascular system. There is an extraordinarily rapid 40% increase in ventricular muscle mass in Burmese pythons (Python molurus) a mere 48 hours after feeding, which results from increased gene expression of muscle-contractile proteins. As this fully reversible hypertrophy occurs naturally, it could provide a useful model for investigating the mechanisms that lead to cardiac growth in other animals^ref.
Web resources :
• The EMBL Reptile Database
• Usenet sci.bio.herp
Web resources :
• Invertebrate pages
• Invertebrate Paleontology Image Gallery from Peabody Collections at Yale University
• Birds
• beak : the forward-projecting jaws of a bird, along with their leathery or horny cover
• wing bud : a swelling on the trunk of an avian embryo that gives rise to a wing
• cortical–basal ganglia circuits have a critical role in motor control and motor learning. In songbirds, the anterior forebrain pathway (AFP) is a basal ganglia–forebrain circuit required for song learning and adult vocal plasticity but not for production of learned song. Neural activity in the AFP of adult birds can direct moment-by-moment changes in the primary motor areas responsible for generating song, a complex, learned motor skill. Song-triggered microstimulation in the output nucleus of the AFP induces acute and specific changes in learned parameters of song. Moreover, under both natural and experimental conditions, variability in the pattern of AFP activity is associated with variability in song structure. Finally, lesions of the output nucleus of the AFP prevent naturally occurring modulation of song variability. These findings demonstrate a previously unappreciated capacity of the AFP to direct real-time changes in song. More generally, they suggest that frontal cortical and basal ganglia areas may contribute to motor learning by biasing motor output towards desired targets or by introducing stochastic variability required for reinforcement learning^ref.
• a bird that lives in the Ecuadorian rain forest attracts mates by striking its wing feathers together behind its back. Birds and other vertebrates usually court partners by expelling air to produce sound. But the male club-winged manakin (Machaeropterus deliciosus) is the first found to use purely mechanical means to produce its 'songs'. This is completely unprecedented in the vertebrate world^ref. The technique is more common in insects such as crickets. Only the male manakins have been spotted making noise this way. Their songs sound like 2 sharp clicks followed by a sustained, violin-like note. That much has been known for a long time: Charles Darwin wrote about the strange manakin sounds in 1871 (Darwin C. The descent of man and selection in relation to sex, (John Murray, London, 1871)). He also noted that the male birds had some feather shafts with thickened ends. Now, > 130 years later, Bostwick and her colleague Richard Prum of Yale University in Connecticut say that the male manakins use these thickened shafts to sing. Using high-speed digital cameras, they show that the birds strike the tips of their wing feathers together behind their backs in a shivering motion at 106 times a second. That's the fastest known limb movement in any vertebrate. It is swifter than the 90 hertz tail movements of rattlesnakes or the 80 hertz wing movements of hovering cuban bee hummingbirds (Calypte helena). It's really fast for a bird that size, but it is not fast enough to explain the frequency of the manakin's sound, which at 1,500 hertz is some 14 times faster than the wing oscillations. The answer came when Bostwick took a closer look at the thickened feather shafts. She found that one of the feathers typically has 6-8 ridges on it, and its neighbouring feather is bent such that it can rub against it. So during every wing shiver (at 106 hertz), the feather rubs against about seven ridges on the way out, and about seven on the way back.
• To prove that this creates the high frequency sound, Bostwick plans to snip off the tip of the neighbouring feather. A bird without that shouldn't be able to make a 1,500-hertz sound. In the meantime, most experts agree her explanation is correct. It's hard to explain the outcome in any other way
• birds that live in bunches work each other up into a reproductive frenzy with their songs, according to research that confirms an old hypothesis. As far back as the 1930s, ornithologists proposed that large, sociable colonies of birds would tend to have earlier, bigger and more closely synchronized clutches of eggs. Known as the Darling hypothesis, after F. Fraser Darling who first suggested the idea, it has finally been supported by experiments in the laboratory. To test Darling's hypothesis, the researchers set up two indoor colonies of the zebra finch (Taeniopygia guttata), a smart little Australian bird often seen in pet shops. The first group of birds was played recorded sounds of its own colony, but the second group heard a playback that blended its own colony sounds with noises from extra finches. Females in the second group had more eggs, laying them earlier and more synchronously than controls, confirming the theory. This mating pattern is probably beneficial for a bird to have its chicks at the same time as the couple on the next nest With more chicks around, the risk to each individual chick from predators is reduced. It is also advantageous for a female to start laying early in the season, because this gives her more time to invest in her brood and makes it likely that she will fledge more chicks successfully. However, laying too early will isolate chicks and put them at risk, so how do females decide when to lay? Finches are known to use environmental cues like rainfall and length of the days, but the experiment by Boag and his colleagues shows that they also respond to bird calls associated with reproduction. After all, if everyone else sounds as if they are laying, it's probably safe to lay your eggs too. A single bird on its own might be right or might be not right but if you have fifty birds reacting to those cues, and if the majority decides it's time to breed and they get excited, then they sing a lot. The volume of social sounds acts as a kind of information feedback loop. It leads almost to a crescendo and feeds upon itself and suddenly, boom: everybody mates. The exact mechanism for the effect is still being worked out, but other studies have shown that hearing social sounds can cause changes in hormone levels in birds.
• several plumage types are found in feral pigeons (Columba livia), but one type imparts a clear survival advantage during attacks by the swiftest of all predators — the peregrine falcon (Falco peregrinus). Quantitative field observations and experiments have been used to demonstrate both the selective nature of the falcon's choice of prey and the effect of plumage coloration on the survival of feral pigeons. This plumage colour is an independently heritable trait that is likely to be an antipredator adaptation against high-speed attacks in open air space^ref.
• brds may hover over or perch on flowers when feeding on nectar, and this assists cross-pollination if they then visit other plants. The function of the curious sterile inflorescence axis of the South African Cape endemic 'rat's tail' plant (Babiana ringens, Iridaceae) — unlike in other bird-pollinated plants — is exclusively to provide a perch for foraging birds. This structure promotes the plant's mating success by causing the malachite sunbird (Nectarinia famosa), its main pollinator, to adopt a position ideal for the cross-pollination of its unusual ground-level flowers^ref.
• does a hummingbird fly like an insect or a bird? A bit like both. What led us to this study was the long-held view that hummingbirds fly like big insects. Many experts had argued that hummingbirds' skill at hovering, of which insects are the undisputed masters, means that the 2 groups may stay aloft in the same way: by generating lift from a wing's upstroke as well as the down. This turns out to be only partially true. Other birds get all of their lift from the downstroke, and insects manage to get equal lift from both up and down beats, but the hummingbird lies somewhere in between. It gets about 75% of its lift from the downstroke, and 25% from the upwards beat. Rufous hummingbirds (Selasphorus rufus) were trained to hover in place while feeding from a syringe filled with sugar solution. They filled the air with a mist of microscopic olive-oil droplets, and shone a sheet of laser light in various orientations through the air around the birds to catch 2D images of air currents. A couple of quick photographs taken a quarter-second apart caught the oil droplets in the act of swirling around a wing. Although hummingbirds do flap their wings up and down in relation to their body, they tend to hold their bodies upright so that their wings flap sideways in the air. To gain lift with each stroke the birds partially invert their wings, so that the aerofoil points in the right direction. Their flight looks a little like the arm and hand movements used by a swimmer when treading water, albeit it at a much faster pace. Insects attain the same lift with both strokes because their wings actually turn inside out. A hummingbird, with wings of bone and feathers, isn't quite so flexible. But the birds are still very efficient. Their wings are a marvellous result of the considerable demands imposed by sustained hovering flight. Provided with enough food, they can hover indefinitely. The researchers add that the hummingbird's flapping bears a striking resemblance to that of large insects such as hawkmoths, an example of how evolution can produce similar engineering solutions in hugely distant animal groups^ref.
• a forest in South Carolina has been peppered with fluorescent bird droppings, all in the name of conservation. The unusual technique was used to track the movement of birds between patches of their preferred habitat after it has been broken up, in this case by stretches of pine trees. The scientists sprayed wax myrtle seeds, a favourite food of eastern bluebirds (Sialia sialis), with fluorescent powder and then tracked the brightly coloured results. Their results support the idea that 'corridors' of native vegetation connecting patches of preserved land will direct birds from one friendly area to another. This movement of birds is good news for biodiversity because it means the seeds in their droppings are widely dispersed. It doesn't matter to the birds how wide these corridors are, which may make it easier to plan and construct such connections. Corridors make sense intuitively, but most experiments have been done on a very small scale. It's darn hard to predict what animals will do on a large scale. To study a larger scale, Levey and his colleagues investigated bluebirds in the Savannah River National Environmental Research Park. The park is composed mainly of managed pine forest, which is not the preferred habitat of the birds. Nestled within the pines, the researchers cleared several sites and allowed native vegetation to grow in these reserves. A central reserve, which contained fruiting wax-myrtle bushes sprayed with powder, was connected by a cleared corridor to another reserve some 150 m away. When team members examined the fluorescent droppings, they found that most of the birds eating the myrtle seeds flew along the corridor to the connected reserve. This helps to prove that corridors actually work. The cleared sites were all square, and observers noted that the birds had a tendency to fly parallel to the edges of these cleared areas, rather than flying off in a random direction. Although the researchers didn't get the opportunity to watch the bluebirds actually flying down the corridors, they think that the birds probably navigate along the edges of these too. If so, it doesn't much matter how wide the corridor is. To a bluebird, a corridor is just a pair of edges. Even a narrow corridor could be used to encourage seed dispersal from one area to another, which would help conservationists^ref.
• It takes brains to make it through the winter, at least if you're a bird. A new survey suggests that bird species that have evolved to fly south for the coldest months tend to be those that weren't smart enough to survive if they stayed put. The study shows that migratory birds, which leave temperate regions in search of warmer climes when temperatures start to dip, have smaller brains than those who stay behind. Non-migrating species also show more creativity when it comes to finding a meal in the frugal winter months. Researchers collected data on brain size, and also counted the number of times researchers had spotted the birds adopting a novel feeding technique in previous observations of 134 bird species in Europe, Scandinavia and western Russia. Species that remain resident during the winter have adopted more feeding innovations^ref. The blackbird, Turdus merula, for example, has been seen using twigs to clear snow away while foraging. And the bullfinch, Pyrrhula pyrrhula, has been spotted tearing flesh from chicken and duck carcasses to get a meal. On average, non-migratory birds have been spotted using four novel feeding styles per species, compared with around three for short-distance migrants, and just over one for species that commute beyond the Sahara Desert to the south. Species with greater foraging flexibility seem to be able to cope with seasonal environments better, while less flexible species are forced to become migratory. A similar pattern was seen in brain size, with the resident species tending to have more upstairs than short-distance migrants, who in turn had larger brains than the long-distance fliers. Brain tissue requires a lot of energy. So migratory birds, which expend a large chunk of their energy commuting, may benefit from having smaller brains to maintain. But, the team argues, small brains probably forced the birds to adopt a migratory lifestyle in the first place, because they were not smart enough to cope with winter. Their lack of inventiveness may mean that migratory species will have more trouble adapting to future changes in environmental conditions. With climate change and human intervention changing the landscape, these birds may be at greater risk of extinction than those that stay put.
• conservationists and bird lovers were thrilled in April 2005 by a videotape^ref, of what seemed to be an ivory-billed woodpecker (Campephilus principalis) in Arkansas. No sighting of the majestic species in the USA had been confirmed since 1944; it disappeared as its dense forest habitat was chopped down, making the bird a symbol of lost heritage. Now a team of ornithologists, led by Richard Prum of Yale University, Connecticut, argues that the bird described is not an ivory-billed woodpecker after all, but a non-endangered relative: a pileated woodpecker (Dryocopus pileatus)^ref. Prum and his colleagues scrutinized a video taken by a Cornell University team in the forested swamps east of Little Rock, Arkansas. Detailed studies of the bird's size and white markings suggest it could be a pileated woodpecker rather than an ivory-billed. The Cornell team had considered this possibility and discounted it. The crucial video includes a 4-second section in which the bird takes off from a tupelo tree in April 2004. Because the camera was mounted on the front of a canoe, and set to a wide focus, the images are frustratingly blurry. Prum declines to discuss details of his manuscript until it is published, in a PLoS journal. The third author of the paper is Mark Robbins, an ornithologist at the University of Kansas in Lawrence, and member of the American Birding Association's checklist committee, which confirms species sightings. John Fitzpatrick, the Cornell ornithologist who led the Science report, and other co-authors also declined to comment. PLoS plans to publish a response from the Cornell team, and a further rebuttal from Prum's group. All 3 papers are expected to go online within a month. The Science paper also included 7 reported sightings by Cornell team members between February 2004 and February 2005 around the Cache River and White River national wildlife refuges. But visual observations can be suspect, and they came amid thousands of observer hours when no other sightings were made. Prum's analysis may have significant implications for policy as well as conservation biology. The Bush administration and congressional Republicans are leading a charge to reduce species protections under the US Endangered Species Act. For > 30 years this legislation has sheltered threatened plants and animals, and infuriated some business and development interests. The ivory-billed woodpecker is covered under the act. In April, after the woodpecker's reported rediscovery, the USDA and the interior redirected about $10 million from other projects to conserve the ivory-billed's habitat. The announcement also triggered a tourist boom for rural Arkansas, with birding enthusiasts flocking to the area for a glimpse of the creature. But the sound recording of the woodpecker's distinctive call and tree rapping, which match old records from the bird's last US sightings in the 1940s and 1930s, has convinced even some of the harshest sceptics that at least 2 of the birds are indeed still around. Richard Prum, a Yale University ornithologist and lead author of the planned critical article, said on Aug 1 that the team has withdrawn their manuscript from PLoS Biology. The new sound recordings provide clear and convincing evidence that the ivory-billed woodpecker is not extinct. The Cornell team handed over the tapes on 31 July, as supporting evidence to PLoS in rebuttal to the Prum team article. Cornell officials are saying little about the tapes as they plan to report them in a scientific forum in the near future. But woodpeckers of the ivory-billed's genus (Campephilus) have a particular double-rapping method, which is evident on the new tape.
• Historical scenarios of evolution of avian plumage coloration have been called into question with the discoveries that most birds can see UV light (which normal humans cannot), and that UV-reflecting plumages are widespread in birds. Several examples of sexual dichromatism not detectable with human visual capabilities suggest that our categorizations of plumages as sexually mono- or dichromatic might often be incorrect. Nonetheless, given the limited taxonomic scope of those examples, the vast majority of sexually monochromatic birds are still treated as such without question in avian research. >90% of 139 species, in a broad sampling of presumed sexually monochromatic passerine birds, were actually sexually dichromatic from an avian visual perspective, based on comparisons of plumage reflectance data using a visual model of color discrimination thresholds. The taxonomic ubiquity of this result suggests that many existing interpretations of evolutionary patterns of sexual dichromatism in birds are erroneous. The visual model used herein provides a method for quantifying sexual dichromatism, revealing that most (58.7%) feather patches sampled lie along a continuum of dichromatism between avian and human discriminatory abilities and could represent unrecognized sexually selected signals. Sexual dichromatism in this study rarely resulted from intersexual differences in UV coloration alone, emphasizing the need for analysis of bird coloration in relation to the full extent of avian visual discriminatory abilities, including, but not limited to, UV-visual capabilities^ref.
• Life history theory predicts that females should vary their investment in offspring according to the quality of their mate. In birds, several studies have now shown that females do vary investment according to perceived male quality, by producing larger eggs, investing more in parental care or by manipulating the sex of their offspring. In a captive breeding colony of canaries, under normal conditions larger eggs in a clutch are more likely to hatch male offspring. In canaries, male song functions in female attraction and females respond more to complex structures in male song called sexy syllables. Females exposed to playback of male song produce larger eggs than those who heard no song. Females exposed to playback of more attractive songs containing sexy syllables, produced larger eggs than those exposed to simpler songs containing no sexy syllables. However, in a final analysis, no evidence was founds that females exposed to pla