Category: Behaviour
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All organisms show behaviour to a certain extent. In animals, behavioural responses are often complex and diverse and, thus, evolutionary convergence in behaviour would a priori be surprising. Indeed, examples of behavioural convergence are rather limited to date (although there are probably many more awaiting recognition), but that they exist at all nicely illustrates the ubiquity of convergent evolution.
While behaviour can be innate, many animals have some capacity for learning. There are striking parallels between cephalopods (notably the octopus) and vertebrates, which extend to associative, observation, and spatial learning. But learning is very widespread, being found in many other groups such as arthropods (particularly insects) and even nematodes. Central to learning is the capacity to memorise and this is convergent as well. Interestingly, sleep, which is probably important for the processing of memories, has evolved many times, not only in mammals and birds, but also in a number of arthropods (e.g. crayfish, fruit flies and honeybees) and probably even in octopus and cubozoan jellyfish. Teaching, where a behaviour is taught by an experienced individual, is not unique to humans either, but can be observed in many animals, including meerkats, birds and ants.
Play is the hallmark of the most intelligent animal species, and there are striking similarities between birds and mammals, with a one-to-one correspondence to the four principal categories of play (chasing, fighting, invitation and object play). While highly characteristic of young mammals, only those birds with complex cognitive abilities (namely crows, hornbills and parrots, particularly kea and kakapo) engage in play. There is also some evidence for play in the octopus.
Behaviour is of particular importance when it comes to mating. In several animals, the male presents a nuptial gift (e.g. food or silk) to the female to increase his chances of fertilisation. This has evolved several times in insects and, more unusually, in spiders. Convergence is also evident in the courtship behaviour of insects (e.g. houseflies, lacewings and crickets) as well as bowerbirds, which is of particular interest as the decorated bowers are very complex. A particularly familiar example of courtship behaviour is lekking. Typically, males display within an arena to visiting females, which then choose a mate. While classical cases occur in birds, lekking is also evident in various amphibians, some mammals, fish and even a number of invertebrates, including some insects, squid and fiddler crabs.
Fiddler crabs are of further interest in the context of behavioural convergence as they demonstrate the independent evolution of surprisingly complex activities, such as defence of their patch, plugging of neighbours' burrows and erection of mud walls. The latter can be considered an example of construction behaviour, which too includes nest building (not only found in birds, but also in chimpanzees) and the construction of similar web types in different lineages of spiders. A number of animals furthermore construct and use tools, which is at its most sophisticated in primates and corvids, but simpler forms of tool use can be observed in other groups, including cephalopods and insects.
Subterranean burrowing mammals illustrate several behavioural convergences. Not only do they show a uniform preference for attacking the lower end of a carrot (!), but many of them are also solitary, show a high level of aggression and employ seismic communication. Several lineages of desert lizards have evolved similar behavioural adaptations to obtain water, such as adopting a stereotyped body posture to maximise water capture.
Societal convergences include matriarchal societies in elephants and sperm whales as well as fission-fusion societies in dolphins, chimpanzees, some New World monkeys and elephants. Perhaps the most remarkable example, however, is the repeated evolution of eusociality in mammals, crustaceans and, most importantly, insects, such as bees and ants. Ants are particularly instructive in terms of behavioural convergence, because several lineages have independently evolved slavemaking and, more benignly, agriculture or the "farming" of other insects (e.g. aphids) for their sugar secretions.
On the more curious side, behavioural convergence is evident in the process of getting drunk, which is very similar in fruit flies and mammals, the reaction to death in humans, elephants and dolphins, the independent evolution of hygiene in a number of insect groups (e.g. ants, termites, butterflies and moths) and feigning death, which may be used as a defensive strategy in many animals, such as cichlids, ants, beetles, and spiders.
| Topic title | Teaser text | Availability |
|---|---|---|
| Gliding in spiders, ants and other arthropods | n/a | Unavailable |
| Bioluminescence | Flying through the air on a summer's evening or sparkling in the ocean you may see magical flashes of light that signal some of nature's most enchanting creatures, those that are bioluminescent. | Available |
| Culture and tradition in animals | n/a | Unavailable |
| Male fish building complex nests to entice females | Japanese pufferfish males expend gargantuan amounts of energy building complex sand nests to attract females, who lay their eggs there. Reminds remind one of bower-birds among others... | Unavailable |
| Electrolocation and electrocommunication in weakly electric fish | Fish have eyes, but they live in a much more complex sensory world, where even electricity plays a surprising - and convergent - role. | Available |
| Daily torpor in birds and mammals | n/a | Unavailable |
| Nest-building in birds | n/a | Unavailable |
| Brood parasitism in cuckoos and other birds | Obligate brood parasitism has evolved several times independently in birds. Apart from the cuckoos, it can be found in four other, only distantly related families. | Available |
| Teaching in humans, meerkats, birds and ants | n/a | Unavailable |
| Agriculture in marine polychaete annelids | Some polychaetes attach pieces of algae to their dwelling tube. Just for decoration? No, but for a much more substantial (and convergent) benefit... | Available |
| Agriculture in wood wasps | The most famous hymenopteran farmers are, without doubt, the attine ants. Rightly so, but they are not the only ones... | Available |
| Agriculture in dugongs | When you think of grazing mammals, you might envisage large herds of antelopes roaming African savannahs. Did you know that there is an equivalent in the ocean, feeding on seagrass? | Available |
| Agriculture in gall midges (Diptera) | Flies, fungi, farming - sounds interesting? Read on if you want to learn about some rather different gall midges... | Available |
| Agriculture in beetles | Think of weevils and most likely you'll think of spoiled food. But some weevils have turned to farming... | Available |
| Agriculture in damselfish | Don’t be tempted to think human agriculture is unique. On many coral rocks, there are very similar things going on… | Available |
| Foam nests in animals | Nests crop up everywhere, but one made out of foam? Might not sound like a great idea, but it is. And no surprise, it has evolved several times... | Available |
| Pufferfish (and inflation) | Pufferfish are some of the most extraordinary fish to have evolved, especially because of their capacity to swallow water and inflate themselves to something like a football. Not only that but some representatives can be deadly to the unwary diner... | Available |
| Moray eels | Eels masquerading as snakes sounds interesting, and that is before they go hunting with their friends the groupers... � | Available |
| Eusociality in alpheid shrimps | A group of coral-dwelling shrimps, the alpheids, have not only evolved eusociality, but managed it several times independently. | Unavailable |
| Feeding in snakes and lizards | The Turtle-headed sea snake feeds on small eggs and its feeding shows intriguing similarities to the way lizards forage, and herbivorous mammals graze and browse. | Available |
| Sociality in mole-rats and meerkats | n/a | Unavailable |
| Thanatosis (feigning death) in spiders and insects | Beetles that "play possum"? A rather interesting example of convergence… | Available |
| Nuptial gifts in insects and spiders | Male dance flies lure females with a dead insect. Not very romantic, you might think, but it certainly does the trick. Hence, such nuptial gifts have evolved in numerous other arthropods... | Available |
| Drinking adaptations in desert lizards | Both Moloch horridus and [...] Phrynosoma cornutum have the remarkable ability to transport water over their skin’s surface to the mouth where drinking occurs. Sherbrooke et al. (2007) Zoomorphology, vol. 126, p. 89 | Available |
| Gregarious butterfly larvae | A particularly interesting example of gregariousness is found in the larvae of some butterflies; not only is it convergent but has evolved more than twenty times. | Unavailable |
| Camouflage in arthropods | Some insects make a “back-pack” of dead ants that evidently deters the attention of jumping spiders, while even more remarkably a weevil living in Papua hosts a garden on its back, complete with moss, algae and other organisms. | Unavailable |
| Biological uses of silk: from webs to ballooning | What material is so versatile that it can be used for capturing prey, building nests, communication and even cleaning? The answer: that most remarkable of biomaterials - silk. | Available |
| Courtship behaviours | n/a | Unavailable |
| Hygiene in insects | n/a | Unavailable |
| Birds: insights into convergence | Intriguing ecological and morphological parallels can be found among the Neoaves. Many of these forms were initially believed to be each other's closest relatives, but are now widely recognised as classic examples of convergence. Think how similar swifts and swallows are, but they are only distantly related. | Available |
| Tool use in birds | What animals can drop stones into a water-filled tube to bring floating food within reach or bend wire to form a hook? Obviously chimpanzees? No, New Caledonian crows have evolved sophisticated tool use too. | Available |
| Eusociality in aphids | A soldier caste has evolved in aphids multiple times. They are typically clonal and equipped with powerful claws or stylets, and in one group even horns. | Unavailable |
| Electric fish: insights into convergence | Ever seen an electric eel in an aquarium? Don’t dare putting your hand in the tank... | Available |
| Butterflies and moths: insights into convergence | Some moths feed on the secretions from the tear-ducts of mammals, and some moths in Madagascar have evolved this independently, but instead of mammals they frequent birds. | Unavailable |
| Raptorial appendages in mantids and other arthropods | The praying mantises exercise a peculiar fascination, not only because of their lunging predatory habits, but also because on occasion the process of copulation ends with a decapitated male being chewed to pieces by the female while the reproductive movements continue. | Unavailable |
| Sleep in animals | Suffering from insomnia? Fruit flies do as well... | Available |
| Agriculture: from ants to dugongs | Human farmers tending their fields are a familiar sight. But don't forget about those fungus-farming termites or the fish with a garden of algae… | Available |
| Beetles: insights into convergence | The beetles are probably the most diverse animal group on earth, so it is not at all surprising that they provide many fascinating insights into convergence. | Available |
| Agriculture in ants: leaf-cutters (attines) and non-attines | In some species, special squads leave the nest early each day, ascend the tree-trunks and then spend hours cutting out pieces of leaf that are dropped to other units on the ground. | Available |
| Woodpeckers and woodpecker-like birds and mammals | You think woodpeckers are unique? Consider the ovenbirds. Or even the curious aye-aye. | Available |
| Eusociality and organisation in (army) ants | Army ants are permanently nomadic, and act as highly co-ordinated units that can form long files or fan out across the forest floor in search of prey. | Unavailable |
| Slavery | n/a | Unavailable |
| Ants: insights into convergence | Trap-jaws, silk and agriculture – just a few examples of convergence in the arguably most successful group of insects, the ants… | Available |
| Fission-fusion societies | Fission-fusion societies has evolved repeatedly and are found, for example, in the elephants, dolphins, chimpanzees, as well as some New World Monkeys. | Unavailable |
| Elephant response to death | Elephants are extremely unusual in their reaction to the dying and death of their compatriots, which includes attempts at resuscitation and grieving. | Unavailable |
| Alcoholism in mammals and flies | Identification of alcohol tolerance (or lack thereof) in different animal groups is important because alcoholism in humans may have some genetic basis. | Unavailable |
| Play in birds, mammals and octopus | Social play is the hall-mark of the most intelligent of this planet’s species, and there is a particularly striking convergence between birds and mammals. | Unavailable |
| Simple tool use in owls and cephalopods | Burrowing owls place pieces of collected dung. These attract insects such as beetles that are then eaten by the owls. | Available |
| Personality in vertebrates and cephalopods | Personality in the vertebrates might, therefore, be deeply embedded in their phylogeny, although this does not rule out the convergent appearance of more complex personality traits in more advanced vertebrates, notably birds and mammals. | Unavailable |
| Lekking in birds, fish, mammals and cephalopods | Complex interactions between males and females prior to mating have evolved independently many times. Amongst the most familiar examples are leks. | Unavailable |
| Burrowing: from worms to vertebrates | Quite a few adaptations are useful for burrowing into the soil. So it is not exactly surprising that they have evolved several times... | Available |
| Asymmetric eye use in octopus, dolphins and birds | In a number of cases one eye is used in preference to another. This convergent phenomenon is found in octopus (cephalopods), dolphins, birds, and other animals. | Unavailable |
| Learning and memory in vertebrates and cephalopods | Convergence in learning (and by implication memory) is important not only because it will give us clues as to the nature of consciousness, but it will also have a bearing on the reality (or otherwise) of pain and suffering in “primitive” animals. | Unavailable |
