Male and female age affects the reproductive potential of two tephritid flies

Abstract

In insects, aging produces deterioration in physiological and cellular functioning, affectingtheir reproductive potential. Anastrepha fraterculus and Ceratitis capitata aretwo fruit fly species where overwintering adults resume their reproductive activityin spring, giving old individuals the possibility of mating with young adults. Most agestudies focus on male reproductive capacity; however, we lack information on howthe interaction between the ages of both sexes can determine post-matingprocesses. Here, we studied sex and age effects on (i) female fecundity and fertility, (ii) failureto leave viable offspring (reproductive failure), and (iii) female remating behavior. Wefound that young pairs of both species had higher fecundity, but young C. capitatamales mated with old females had the lowest fecundity. This suggests that overwinteringflies in this species will not substantially contribute to the next generation. We alsofound in C. capitata more prevalent reproductive failure in hetero-agecombinations, which could be due to age recognition between mates, resulting perhaps in differential ejaculate allocation. Copula duration was positively associated with female age,yet it was longer for older A. fraterculus females and shorter for C. capitata females.Female remating was lower when young females mated with old males in C. capitata.This would imply that males perceive young females of “good quality” and thus investand transfer all the ejaculate possible to ensure the delay of renewal of female receptivity.Aging does not always cause a decline in reproductive potential, which may beimportant in species that overwinter as adults. Complex interactions between femalephysiology and male ejaculate senescence can impact postcopulatory behaviors thataffect reproductive success for both sexes.