The evolutionary causes and consequences of task specialisation during biparental care

Supervisor: Prof Rebecca Kilner

Co-Supervisor: Prof Walter Federle

Sexual dimorphism is conventionally thought to be the result of competition within each sex: for mates, or for resources, or for social dominance. 

This project will consider a novel alternative: can sexual dimorphism also result from instances of cooperation (where cooperation is defined as behaviour that has evolved to promote the fitness of conspecifics as well as the actor itself)? Theoretical analyses suggest that cooperation is more likely to be evolutionarily stable when there is division of labour among cooperating individuals. Each member of the team then becomes a task specialist – and dependent on other team members for the effective completion of other essential activities. Specialisation might then select for a specific morphology or physiology, for the more effective completion of the task at hand. You will focus on parental care as a form of cooperation.

Do divergent selection pressures also operate on the sexes during biparental care, due to the way in which the different tasks of parental care are divided between males and females when they work together to raise offspring? You will test this idea with state of  the art imaging, biomechanical, behavioural and evolutionary experiments, and investigate its broader significance with comparisons among natural populations of the same species, and comparisons across species using Museum samples. You will focus on the burying beetle Nicrophorus vespilloides in which the sexes are almost identical, except for the size of their heads: males have wider heads than females.

References

Shine, R. 1989 Ecological causes for the evolution of sexual dimorphism: a review of the evidence. Quarterly Review of Biology vol. 64 pp 419-461 doi/10.1086/416458

Scott, M. P. 1998 The ecology and evolution of burying beetles. Annual Review of Entomology vol. 43 pp 595-618 doi/abs/10.1146/annurev.ento.43.1.595

Jarrett, B. J. M. et al. 2022 Multilevel selection leads to divergent coadaptation of care-giving parents during pre-hatching parental care. BioRxiv 2022.05.23.493134