Ecology of predator prey interactions in the context of mate searching

Abstract

Animals communicating in the context of mate searching benefit by increasing their likelihood of encountering mates. Mate searching begins the important process of individuals of opposite sexes forming pairs, which is necessary for achieving mating success and improving their chances of attaining reproductive success. But mate searching individuals also experience costs of being conspicuous to unintended receivers such as eavesdropping predators. Prey respond to and manage such predation risk by typically reducing activity or moving away from the risk. Such alteration in behaviour can have potential costs on foraging and mating opportunities. Costs of such behavioural management of risk on an ecological timescale have been studied extensively in the foraging context but have not received enough attention in the reproduction context. Hence, my thesis aims at understanding the ecology of predator-prey interactions in the context of mate searching, using the tree cricket Oecanthus henryi as a model system. I first estimated the relative predation risk experienced by communicating and noncommunicating, male and female crickets from their primary predators, green lynx spiders, at multiple spatial scales. I then manipulated predation risk in enclosure experiments and observed how it affects communication and survival, to compare their relative fitness consequences. Finally, I examined how crickets and spiders use space at two different spatial scales, in order to explore whether crickets behaviourally manage the risk they experience while searching for mates. Before observing how prey respond to predation risk, it is important to estimate what risk they face in nature. And since mate searching typically has two strategies of pair formation, including signalling and responding to signals, with each generating different cues, it is vital to know whether the risk these strategies face are different. Hence, I estimated predation risk of mate searching in natural cricket populations, at multiple spatial scales at which p...