Flight during oviposition reduces maternal egg provisioning and influences offspring development inPararge aegeria(L.)

Abstract

As a result of increased habitat fragmentation in anthropogenic landscapes, flying insects may be required to travel over larger distances in search of resources such as suitable host plants for oviposition. The oogenesis-flight syndrome hypothesis predicts that physiological constraints caused by an overlap in the resources used by thoracic muscles during flight and during oogenesis (e.g. carbohydrates, lipids and water) result in a resource trade-off, with any resources used during flight no longer available for reproduction. Increased flight costs could therefore potentially result in a decrease in maternal provisioning of eggs. In the present study, the speckled wood butterfly Pararge aegeria (L.) is used to investigate whether increased flight during oviposition results in changes in maternal investment in eggs and whether this contributes to variation in the development of offspring in subsequent life stages. Forcing females to fly during oviposition directly influences egg size and embryonic development time, and indirectly influences (through changes in egg size) egg hatching success and larval development time. These effects are mediated through 'selfish maternal effects', with mothers forced to fly maximizing their fecundity at the expense of investment to individual egg size. The present study demonstrates that a change in maternal provisioning as a result of increased flight during oviposition has the potential to exert nongenetic cross-generational fitness effects in P. aegeria. This could have important consequences for population dynamics, particularly in fragmented anthropogenic landscapes.