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Entomological Society of Victoria N e w s l e t t e r No. 10 June 2016 INDEX Do insects have personalities? by Patrick Honan Do insects have personalities?...…………….1 If you’ve ever seen a mating pair of Rhinoceros Beetles with their heads buried deep in soft banana, you’d have to say that Rhino From the archives...…….....5 Beetles know how to enjoy themselves. Meet your ESV Council…...7 But do they have personalities? The question is answerable ESV Council…….…............8 partly from a scientific perspective, but also whether 2016 City of Melbourne their behaviour fits the human Urban Bioblitz…………..….9 understanding of what constitutes a personality. Articles of interest………..10 A cantankerous female Blue Ant (Diamma bicolor), actually a Flower Individual species definitely Wasp of the Family Tiphiidae. show distinctive behavioural Around the Societies.........23 traits. Anyone who’s met a Blue Ant (Diamma bicolor), for example, will know how hostile they can Conferences……….……..24 be, whilst Steel-blue Sawflies (Perga dorsalis) are contractually gregarious, and most Raspy Cricket species (Family Gryllacrididae) ESV calendar 2016………25 appear to be perpetually outraged and will come at you from across the room (which makes them so appealing). New publications…………25 Many people who know insects tend to anthropomorphise the species they know best. The Garden Mantid (Orthodera ministralis) is confident and curious, but can turn in a heartbeat into a skilled and clinical killer. Greengrocer Cicadas (Cyclochila australasiae) are loud and raucous – the Sulphur-crested Cockatoos of the Steel-blue Sawfly larvae (Perga insect world. Bushflies (Musca species) gathering on a eucalypt vetustissima), on the other hand, branch during the day. They move out to feed collectively at night. are sharp and nimble, whereas www.entsocvic.org.au Marchflies (Family Tabanidae) are dense and clumsy, the dummkopfs of the fly world. 1 Tarantula keepers may interact daily with their A male charges over many years, sometimes with Greengrocer Cicada several specimens of the same species at the (Cyclochila same time, and will get to know their individual australasiae), peculiarities. the cockatoo of the insect world. It makes sense from an evolutionary perspective for there to be variation between the behaviour of individuals, no matter what the species. After all, variation is one of the Spiders too can be anthropomorphised. means by which individuals survive or perish in Jumping Spiders (Salticidae) are the least highly variable environments. In a high threatening of the arachnids – alert, highly predator environment, individuals that are more observant and very perceptive. They are the ‘shy’ are less likely to be eaten, whereas in a most clown-like of the spiders (Mopsus mormon food-poor environment, the ‘bold’ individuals sometimes goes by the name ‘Clown Spider) that roam further looking for food are more and seem to be forever showing off. On the likely to survive. other hand funnelwebs, especially the Sydney Funnelweb (Atrax robustus) are infamously sinister and quick to threaten. Many people swear that huntsmans chase them, and Badge A rearing Sydney Spider (Neosparassus diana) even appears to Funnelweb have a scowl on its ‘face’ as it rears up with Spider fangs agape. (Atrax robustus). It can be difficult to assess the personality traits of short-lived insects, particularly in the field, but spider-lovers with experience in exotic , long-lived, tarantulas will recognise differences In fact bold vs shy is one of the easiest between the placid Chilean Rose Tarantula personality traits to measure, and therefore the (Grammostola rosea) and the cantankerous but most widely tested on animal species, including harmless King Baboon Tarantula (Pelinobius insects and spiders. Boldness can be measured muticus). In terms of speed, aggression and by the time taken by an animal to resume bad temper, nothing compares with the local normal behaviour after it faces a threat of some Australian tarantulas (including Selenocosmia, sort. A spider, for example, may curl up into a Selenotypus and Phlogiellus). ball after being treated to a puff of breath similar to that of a foraging bird. Bold These behaviours may be known as derived individuals will uncurl in less than a minute, whilst shy individuals may take an hour or more, and that time can be used as a direct The Clown measure of ‘boldness’. Jumping Spider Aggression is another personality trait that can (Mopsus be readily measured, either towards prey, mormon) predators or members of the same species. Individual spiders within a single species are known to vary in levels of aggression, and those that reside at either end of the spectrum traits, characteristics that are unique to a are unlikely to succeed in evolutionary terms. species and shared by all members of that An individual that is aggressive towards prey species. But by definition, personalities (also will grow more quickly but is more likely to take classified as temperaments or behavioural on and succumb to oversized prey that can syndromes) must differ between individuals of fight back. A female spider that is aggressive the same species, not between species. towards any approaching movement is likely to 2 after disturbance. Scientists studying American March Flies Cockroaches (Periplaneta americana) at the (Tabanidae) are unfortunately Universite Libre de Bruxelles in Belgium found gruesome but similar patterns in behaviour, and additionally fortunately, while individuals within a group demonstrated a unlike bushflies, slow and range of behavioural traits, these were modified cumbersome. into a group ‘personality’ under certain circumstances. capture sufficient prey to eat well, but will kill Somewhere in between species and individual, all potential partners and therefore fail to social spiders may exhibit ‘personality’ at the breed. A female that recoils from approaching colony level. Researchers at the University of movement will not only miss passing prey, she Pittsburgh found that colonies of the African will avoid mating altogether. Somewhere in social spiders (Stegodyphus sarasinorum and between are successful individuals that chase S.dumicola) differed from each other in levels small prey but avoid tackling too-large prey, of boldness, but that within colonies, individuals and allow potential suitors to approach without behaved consistently both as a group and consuming them, at least until mating is individually over time. When spiders with complete. different levels of boldness where transferred between colonies, the researchers found the Other personality traits are also measurable level of a colony’s boldness was determined by and appear to be widely expressed by insects. that of the boldest individual within a colony. A Within a species of insect, there may be very bold individual transferred to a shy colony individuals with a greater tendency to explore would ‘inspire’ its new colony mates to be four (a ‘curious’ personality, technically called times bolder than they would otherwise be. explorativeness), or be more ready to defend than retreat (brave, or perhaps foolhardy), be A male and female Social more or less active (busy versus lazy), able to Huntsman modify behaviour under varying circumstances (Delena (adaptable), or willing to be close to or tolerate cancerides) courting under other members of the same species bark. A single (gregarious). All these traits would be colony may considered part of a personality when house up to 300 individuals. expressed in humans, and all are adaptive traits that assist in survival of insects and spiders in the wild. Research on social spiders in general suggests that spiders’ lower aggression levels enable American them to tolerate other members of the same Cockroaches (Periplaneta species and therefore live communally, but are americana) also less aggressive towards prey and potential feeding on predators. Sociality in spiders is perhaps most compost. In these highly evolved in the Australian Social situations Huntsman (Delena cancerides), which are not they can only tolerant of other nest members but develop a ‘group regularly bring back prey to share with the personality’. colony. Dominant females will tolerate juvenile members of other colonies moving into the And the theory is backed up by recent research. nest, but she draws the line at allowing in adult Studies conducted at Universities in Hungary females from other nests. Research on Social and Denmark found individual European Huntsmans is still in its early days, but there’s Firebugs (Pyrrhocoris apterus) were every chance individual variation in consistently either ‘shy’ or ‘bold’, as determined personalities within a colony will be discovered. by how long they took to emerge from a refuge 3 Extending these personality traits into the lesser reward, remarkably similar to the hypothetical, we can speculate that consistent standard reaction in vertebrates. personality differences may lead to caste differentiation in social insects and spiders – These studies show that, in insects and spiders, those that are more bold or aggressive would behaviour not only differed between individuals, be most effective in defending the colony, for but was consistent within individuals across a example, whilst individuals with tendencies range of situations. This is the very definition of towards explorativeness would make excellent a personality trait. So the short answer to the foragers. This is known as ‘social niche question ‘Do insects have personalities?’