Effects of Elevated Predation Risk on Female Mate Selection and Maternal Effects in Trinidadian guppies

Predation carries a number of non-consumptive i.e. non-lethal behavioural effects over daily, seasonal, yearly, and generational time scales through which population-level changes in innate antipredator behaviour can occur. Two proposed ways through which these changes may occur are by (1) shaping female mate selection decision-making behaviours to reduce the risk of a predation event, and (2) by improving offspring fitness through anticipatory maternal effects on offspring antipredator behaviour. While changes in antipredator behaviour under these conditions have been noted under acute and long-term risk, similar studies looking at populations reared under short-term elevated background predation risk are lacking. In this thesis, I looked at the impact of elevated predation risk over a period of several days on the reproductive behaviours of female Trinidadian guppies (Poecilia reticulata) and their offspring. In my first experiment, I exposed adult female guppies to intermediate and elevated ambient short-term predation risk and predicted that female guppies would reduce their preference for brightly coloured males and exhibit increased antipredator behaviours. I tested this by measuring the guppy’s latency to enter, sexual activity, time spent with the blue male, and sampling frequency. I found no evidence of intermediate and elevated ambient short-term predation risk affecting female mate preference nor antipredator behaviours. In the second experiment, I examined the impact of elevated maternal predation risk on the antipredator behaviour of Trinidadian guppy offspring. I did this by exposing pregnant female guppies to elevated predation risk and subsequently measuring the antipredator behaviours of their offspring. I predicted that offspring of female guppies under elevated predation risk would exhibit increased dispersal, exploratory behaviour, and neophobic predator-avoidance behaviour. I tested this by measuring offspring response to a novel odour, total distance travelled, mean velocity, number of darts, average acceleration of darts, and time spent paused. I found no evidence of elevated predation risk affecting offspring antipredator responses nor inducing neophobia. Overall, the results of the female mate selection experiment and the anticipatory maternal effects experiment did not provide evidence of elevated predation risk over short-term time frames altering reproductive behaviour in Trinidadian guppies. My results stand in contrast to similar research on wild fish populations and thus additional research is needed to understand the role of short-term predation risk on Trinidadian guppy reproductive behaviours