We determined the effect of body size and adult female longevity on the realized fecundity and fertility of the large aspen tortrix, Choristoneura conflictana (Walker) (Lepidoptera: Tortricidae), an outbreaking forest lepidopteran. We examined these relationships from an ecological perspective and included the impact of age at pairing and infection with a microsporidian pathogen in our analyses. The relationship between body size, as measured by pupal weight and forewing length and area, and realized fecundity and fertility was best for healthy females that were paired immediately after eclosion. A delay in age of pairing or sublethal pathogen infection eroded these relationships. A delay in age of pairing resulted in a lower percentage of females that produced fertile eggs and a significant reduction in the number of eggs laid. Although sublethal pathogen infection indirectly disrupted the body size-realized fecundity and fertility relationship, infection did not directly decrease egg production. Wing area was the best predictor of total and fertile egg production. The relationship between pupal weight and wing area was correlated, but females eclosing from small pupae had proportionately larger wings than females from large pupae, which may indicate a cost of large body mass in this actively dispersing species. Longevity of females did not predict the total or fertile number of eggs laid by females. There was no consistent relationship between pairing treatment and longevity of female moths, suggesting that there is no trade-off between longevity and reproductive fitness in this species. Sublethal pathogen infection significantly decreased female moth longevity, but this decrease was not reflected in reduced fecundity of infected females. Our data illustrate that although body size is an important determinant of realized fecundity and fertility in C. conflictana, these relationships are mediated by several factors that may vary greatly under field conditions and at varying population densities.
Annals of the Entomological Society of America
Vol. 99 • No. 5
Vol. 99 • No. 5
large aspen tortrix