Dispersal, endosymbiont abundance and fitness-related consequences of inbreeding and outbreeding in a social beetle

Martin Tremmel, Hadas Steinitz, Adi Kliot, Ally Harari, Yael Lubin

Research output: Contribution to journalArticlepeer-review


Most social species outbreed. However, some have persistent inbreeding with occasional outbreeding, and the decision of the individual regarding whether to stay in the natal group and inbreed or to disperse, with the potential to outbreed, is flexible and may depend on social, genetic and ecological benefits and costs. Few of these factors have been investigated experimentally in these systems. The beetle Coccotrypes dactyliperda Fabricius, 1801 (Scolytidae: Xyloborinae) lives in extended family colonies inside date seeds. The beetles inbreed, but some individuals disperse away from the natal seed and may outbreed. We investigated dispersal behaviour and assessed fitness-related measures in inbred and outbred offspring, in addition to the relative abundance of two endosymbionts. We predicted inbred offspring to have higher fitness-related measures and a reduced tendency to disperse than outbred offspring, owing to fitness benefits of cooperation within the colony, whereas increased endosymbiont abundance will promote dispersal of their hosts, thus enhancing their own spread in the population. Dispersing beetles were more active than ones that remained in the natal seed. As predicted, fewer inbred offspring dispersed than outbred offspring, but they matured and dispersed earlier. Fitness-related measures of inbred mothers were either lower (number of offspring) or not different (body mass) from those of outbred mothers. Inbred dispersers had greater amounts of Wolbachia, suggesting a role in dispersal. The results support the hypothesis that inbred females reduce dispersal and that early maturation and dispersal are likely to be benefits of increased cooperation in brood care.

Original languageEnglish
Pages (from-to)717-727
Number of pages11
JournalBiological Journal of the Linnean Society
Issue number3
StatePublished - 28 Feb 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2020 The Linnean Society of London, Biological Journal of the Linnean Society.


  • Wolbachia
  • bark beetle
  • cooperation
  • date seed
  • haplodiploid -movement

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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