Did you know that Norwegian rats will trade being groomed for food? How about that female fruit flies become twice as aggressive toward other females after mating? Or that white sharks put the sun behind them like fighter pilots so their targets can't see them properly?
It’s not surprising if you didn’t, because these are all new discoveries revealed at Behavior 2015, a world conference of animal (and occasionally human) behavior happening now in Cairns. Over the next few days we’re hoping to bring you detailed articles on some of the 913 presentations at the conference, but meanwhile, here is an introduction to five that lend themselves to quick summaries.
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Urbanization is bad for lizard society too. Male rock agamas (Psammophilus dorsalis) on the edges of Bangalore are showing signs of higher stress than their rural counterparts. They are more aggressive to fellow males and slower to engage in mating behavior when meeting a female, according to Anuradha Batabyal of the Indian Institute of Science.
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Damselfish (Pomacentridae) release chemicals when attacked by predators. Dr Oona Lönnstedt, of Uppsala University, Sweden, reported that the brown dottyback Pseudochromis fuscus keeps a nose out for these alarm chemicals, telling it that there is a meal around. On smelling the damselfish’s signal, P. fuscus swims in, sometimes eating the damselfish itself, but also leading to a 35–40% increase in the chances of the smaller fish escaping in the confusion. Naturally Lönnstedt called the talk “damsel in distress”.
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When threatened by a predator, male and female Trinidadian guppies (Poecilia reticulata) respond very differently, according to Professor Pierre J-C Chuard of Concordia University, Canada. The females freeze, presumably in the hope that the predator won’t see them. Males, on the other hand, prefer to show off to the females, whose stillness might make them more attentive. Sure the males might get eaten, but if they don’t, their chance of sex goes up, and that's what really matters.
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While on the subject of sex-obsessed males, Giselle Muschett of Sydney’s Macquarie University investigated whether male chameleon grasshoppers (Kosciuscola tristis) prefer virgin mates. The answer is mixed. The males are just as keen to mate with females that have had sex before, but spend up to 10 times longer doing the deed with unmated females. It is believed that, as with many other species, the males use a sort of “plug” to make it harder for those that come after them to mate with a female, and subsequent males, realizing their chance of successful insemination is lower, don’t put in the time.
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Animals not only cooperate across species, they pay attention to each other's attention. Alex Vail of the University of Cambridge studied the cooperative hunting of leopard coral grouper fish (Plectropomus leopardus) and moray eels. Vail reveals that the fish doesn't only behave in ways that send signals to the eel about when to attack, but changes its activity depending on whether the eel is paying attention and “strategically alters its behavior based on the moray’s reactions to its signals.”