Mate-searching context of prey influences the predator–prey space race

Predators generally move towards prey in search of a meal. Far from being easy targets, prey proactively avoid predators at multiple spatial scales, to reduce risk. But prey cannot focus all their efforts on evading predators since they have other crucial tasks to accomplish, such as foraging and reproduction. In Torsekar and Thaker (2020), we show how reproductive behaviour of prey affect their spatial games with predators.

Animals belonging to many taxa search for mates by producing signals and responding to them. These signals allow individuals to form pairs and generally lead to higher mating success. As a part of mate searching behaviour, immobile males signal their availability and location, and mobile females use those signals to localise males and mate with them. Such varying mobility may lead to differential overlap with predators that are tracking prey not only by eavesdropping on signals, but also based on the predictability of their locations. Furthermore, given the overlap with predators, individuals might avoid predators differently depending on their mate searching behaviour. We tested these hypotheses in tree crickets that live on short bushes, just like their predators, green lynx spiders, which move within and across bushes to actively hunt.

We quantified the proportion of bushes inhabited by spiders when crickets are present and absent separately for calling males, non-calling males and females. We found that spiders were present in higher proportions when calling males and females are present on the bush, but not for non-calling males. When a cricket and spider are experimentally manipulated to co-occur on the same bush, phonotactic females move away from the spider and, surprisingly, males move towards them, potentially as a predator inspection strategy. Hence, we found that the sex and mate-seeking behaviour of individual tree crickets influenced the degree of overlap with predators and their antipredator movement strategies, suggesting that reproductive strategies within a prey species can alter predator–prey space race at multiple spatial scales.

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Article - https://royalsocietypublishing.org/doi/10.1098/rspb.2020.1462