Slower senescence in a wild insect population in years with a more female-biased sex ratio

Rolando Rodríguez-Muñoz, Jelle J. Boonekamp, David Fisher, Paul Hopwood, Tom Tregenza* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Citations (Scopus)
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Abstract

Life-history theories of senescence are based on the existence of a trade-off in resource allocation between body maintenance and reproduction. This putative trade-off means that environmental and demographic factors affecting the costs of reproduction should be associated with changes in patterns of senescence. In many species, competition among males is a major component of male reproductive investment, and hence variation in the sex ratio is expected to affect rates of senescence. We test this prediction using nine years of demographic and behavioural data from a wild population of the annual field cricket Gryllus campestris. Over these generations, the sex ratio at adulthood varied substantially, from years with an equal number of each sex to years with twice as many females as males. Consistent with the predictions of theory, we found that in years with a greater proportion of females, both sexes experienced a slower increase in mortality rate with age. Additionally, phenotypic senescence in males was slower in years when there were more females. Sex ratio did not affect the baseline mortality rate in males, but females suffered higher age-independent mortality rates when males were in short supply.

Original languageEnglish
Article number20190286
JournalProceedings of the Royal Society B: Biological Sciences
Volume286
Issue number1900
Early online date3 Apr 2019
DOIs
Publication statusPublished - Apr 2019

Keywords

  • gryllus
  • cricket
  • senescence
  • ageing
  • life-history trade-off
  • sexual selection

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