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Sex, Color, and Mate Choice in Guppies | Princeton University Press
We've seen in our simulations that the more brightly colored a male guppy is, the more likely he will be seen -- and eaten -- by a predator. In a simulation or in the wild, where predators are plentiful, male guppies become increasingly drab over generations, pushed by predation pressure toward greater camouflage. So if camouflage confers such an obvious survival benefit to prey species like guppies when it comes to predator avoidance, what possible advantage could there be to sporting colors and patterns that make an individual more conspicuous? The answer lies in the fact that guppies have to do more than just survive. They also have to reproduce -- and to do that, they have to attract mates. The "flashier" a male guppy is, the more likely a female guppy will choose him as a mate, giving him the opportunity to pass his genes along to the next generation.
Guppies show sex and individual differences in the ability to inhibit behaviour
A properly dressed male guppy, with its gaudy blue spots and brilliant splashes of orange, can't help but stand out. But for a fish that spends its life swimming among predators, it seems that good camouflage would have a big advantage over colors that attract attention. If flashiness is a liability, why are these little guys such exhibitionists? To see the range of coloration that guppies exhibit in the wild, and to see their predators and habitats, check out the Guppy Gallery.
In humans, individual and sex differences have been long reported for several cognitive tasks and are at least in part due to variability in the function that inhibits behaviour i. Similar evidence of individual and sex differences in inhibitory abilities is also present in other vertebrates, but is scarce outside primates. Experiments on reversal learning, which requires inhibiting behaviours, suggest that this variability may exist in a teleost fish, the guppy, Poecilia reticulata. We tested this hypothesis by observing guppies in an inhibitory task.