Understanding the evolution of senescence is a central question in evolutionary biology. Senescence is marked by age-specific declines in survival and fecundity, and as a decline in fitness would seem maladaptive at any age, the reasons for its existence have intrigued evolutionary biologists for decades. One proposed explanation for the evolution of senescence is the existence of a trade-off between reproduction and somatic maintenance (the cost of reproduction). Under the declining strength of selection that occurs with age, trade-offs that benefit early li! fe reproduction are expected to be favoured even if they have detrimental effects on late life survival. If such a trade-off exists, individuals reproducing at faster rates are expected to show faster rates of senescence. Previous studies have found evidence for this cost of reproduction in the laboratory, but few studies concerning natural populations exist. This project aims to examine this trade-off in a natural population of the water strider Gerris buenoi through the use of mark-recapture techniques.
Penelope Gorton, Ecology and Evolutionary Biology, University of Toronto