Playing it safe? behavioural responses of mosquito larvae encountering a fish predator

Predation is a strong selective force that affects prey population and ecosystem dynamics. Detecting predators and associated levels of threat is crucial to prey responses. Once a predator is detected, anti-predatory responses improve the chances of survival of prey. We used Aedes aegypti larvae to study behavioural responses to predation threat from guppies (Poecilia reticulata). Specifically, we tested the relative importance of chemical cues, both in isolation and in combination with physical cues, in eliciting anti-predatory behaviours. Larvae responded more strongly, by reducing the lengths of their wriggle bursts, when presented with a combination of chemical and physical cues than with chemical cues alone. Anti-predatory responses often come with an associated cost, and we expect that the ability to pay these costs should influence responses to predation risk. To test this, we compared wriggling patterns of satiated vs starved larvae in the same experiment. We found that, under p...