Early interactions with adults mediate the development of predator defenses in guppies

Antipredator defenses in many species have been shown to exhibitphenotypic plasticity in response to variable predation risk.Some evidence suggests that in certain species adults act asproxy predators, triggering the development of adaptive defensesin juveniles where interaction with a predator is unlikely tooccur. However, almost nothing is known about how adult/juvenileinteractions mediate plasticity. Here, we examine the natureof the antipredator defenses that develop in Trinidadian guppiesas a function of early social experience and investigate theimportance of different types of cue (physical, visual, andolfactory) by rearing juveniles under 3 different social conditions.In the first, only juveniles are present; in the second, onlyvisual and olfactory interaction occurs between adults and juveniles;and in the third, adults physically interact with juveniles.Our analyses show that juveniles reared in the physical presenceof adults spend significantly less time shoaling with adultsthan fish from other treatments in an adult versus juvenileshoal-choice trial. Further, we show that juveniles with experienceof adult aggression have a decreased response latency to a simulatedavian predation attempt and travel a greater distance in thefirst 5 frames of movement after the simulated strike. Finally,juveniles reared with physical experience of adults developedrelatively deeper bodies and were significantly shorter in standardlength than guppies reared without physical experience of adults.