Quantitative genetic analysis of dispersal in Epiphyas postvittana. II. Genetic covariations between flight capacity and life-history traits

Abstract

On the basis of investigations of environmental and genetic variation in flight capacity of the light brown apple moth, Epiphyas postvittana (Walker) (Tortricidae), genetic covariations between flight capacity and life-history traits in this species were studied by means of sibling analysis and artificial selection. Both sibling analysis and artificial selection strongly evidenced the existence of additive genetic covariances between flight capacity and life-history traits such as developmental time, adult body weight at emergence, age at first reproduction and fecundity. Flight capacity was negatively correlated with adult body weight, the number of eggs laid during the first 5 days of adult life and total fecundity, whereas it was positively correlated with developmental time from egg-hatch to adult emergence, age at first reproduction and adult life span. These results, which indicate that increased flight capacity is accompanied by a slower developmental rate, smaller body size, delayed oviposition and less fecundity, resulting in a lower population growth rate, contrast with the colonizing syndrome that highly mobile individuals show rapid development, early reproduction and high fecundity. It is suggested that the existence of genetic ‘trade-offs’ between flight capacity and these life-history traits is partially responsible for the general occurrence of variability in dispersal capacity by flight in this species.