Adaptive suicide : is a kin-selected driver of fatal behaviours likely?
Abstract
While several manipulated host behaviours are accepted as extended phenotypes of parasites, there remains debate over whether other altered behaviours in hosts following parasitic invasion represent cases of parasite manipulation, host defence or the pathology of infection. One particularly controversial subject is 'suicidal behaviour' in infected hosts. The host-suicide hypothesis proposes that host death benefits hosts doomed to reduced direct fitness by protecting kin from parasitism and therefore increasing inclusive fitness. However, adaptive suicide has been difficult to demonstrate conclusively as a host adaptation in studies on social or clonal insects, for whom high relatedness should enable greater inclusive fitness benefits. Following discussion of empirical and theoretical works from a behavioural ecology perspective, this review finds that the most persuasive evidence for selection of adaptive suicide comes from bacteria. Despite a focus on parasites, driven by the existing literature, the potential for the evolution of adaptive suicidal behaviour in hosts is also considered to apply to cases of infection by pathogens, provided that the disease has a severe effect on direct fitness and that suicidal behaviour can affect pathogen transmission dynamics. Suggestions are made for future research and a broadening of the possible implications for coevolution between parasites and hosts.
Citation
Humphreys , R K & Ruxton , G D 2019 , ' Adaptive suicide : is a kin-selected driver of fatal behaviours likely? ' , Biology Letters , vol. 15 , no. 2 , 20180823 . https://doi.org/10.1098/rsbl.2018.0823
Publication
Biology Letters
Status
Peer reviewed
ISSN
1744-9561Type
Journal item
Description
Funding: Perry Foundation and the University of St Andrews.Collections
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