Social Familiarity Reduces Reaction Times and Enhances Survival of Group-Living Predatory Mites under the Risk of Predation

Markus Andreas Strodl,Peter Schausberger,Maud Ferrari

doi:10.1371/journal.pone.0043590

Markus Andreas Strodl, Peter Schausberger + Show 1 more

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https://doi.org/10.1371/journal.pone.0043590

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Abstract

BackgroundSocial familiarity, which is based on the ability to recognise familiar conspecific individuals following prior association, may affect all major life activities of group-living animals such as foraging, reproduction and anti-predator behaviours. A scarcely experimentally tested explanation why social familiarity is beneficial for group-living animals is provided by limited attention theory. Limited attention theory postulates that focusing on a given task, such as inspection and assessment of unfamiliar group members, has cognitive and associated physiological and behavioural costs with respect to the attention paid to other tasks, such as anti-predator vigilance and response. Accordingly, we hypothesised that social familiarity enhances the anti-predator success of group-living predatory mites, Phytoseiulus persimilis, confronted with an intraguild predator, the predatory mite Amblyseius andersoni.Methodology/Principal FindingsWe videotaped and analysed the response of two P. persimilis larvae, held in familiar or unfamiliar pairs, to attacks by a gravid A. andersoni female, using the behavioural analyses software EthoVision Pro®. Familiar larvae were more frequently close together, reacted more quickly to predator attacks, survived more predator encounters and survived longer than unfamiliar larvae.SignificanceIn line with the predictions of limited attention theory, we suggest that social familiarity improves anti-predator behaviours because it allows prey to shift attention to other tasks rather than group member assessment.

Highlights

Predation is a major selective force shaping the behaviour of prey [1,2]
In line with the predictions of limited attention theory, we suggest that social familiarity improves antipredator behaviours because it allows prey to shift attention to other tasks rather than group member assessment
The shorter reaction times suggest that social familiarity allowed the mites to shift attention from attentiondemanding neighbour assessment to anti-predator vigilance, in accordance with limited attention theory [7,8,21], and enhanced their survival under predation risk

Summary

Introduction

Predation is a major selective force shaping the behaviour of prey [1,2]. To enhance survival under predation risk, animals evolved various behavioural anti-predator mechanisms such as crypsis, defensive or fleeing behaviours, or grouping together to enhance dilution or collective vigilance [3,4]. Group-living may have partly evolved to reduce predation risk because solitary animals have a relatively limited ability to process multiple information and perform multiple tasks simultaneously, e.g. foraging and anti-predator vigilance [3,5,6,7,8,9,10,11]. Social familiarity, which is based on the ability to recognise familiar conspecific individuals following prior association, may affect all major life activities of group-living animals such as foraging, reproduction and anti-predator behaviours. Limited attention theory postulates that focusing on a given task, such as inspection and assessment of unfamiliar group members, has cognitive and associated physiological and behavioural costs with respect to the attention paid to other tasks, such as anti-predator vigilance and response. We hypothesised that social familiarity enhances the anti-predator success of group-living predatory mites, Phytoseiulus persimilis, confronted with an intraguild predator, the predatory mite Amblyseius andersoni

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