Female Mating Frequency and Reproductive Fitness in the Willow Leaf Beetle (Coleoptera: Chrysomelidae)

Effects of Delayed Mating on Mating Performance and Reproductive Fitness of the Willow Leaf Beetle (Coleoptera: Chrysomelidae) under Laboratory Conditions

Simple Summary

Mating disruption is one of the most effective methods for pest management. The willow leaf beetle Plagiodera versicolora Laicharting is a serious pest of poplar and willow. We studied the effects of delayed mating on the mating performance and reproductive fitness of P. versicolora, as part of an effort to control P. versicolora using mating disruption. Delayed mating of females and males impacts their mating performance, but has only a limited impact on the females’ reproductive fitness. These results indicate that delayed mating is unlikely to contribute to the success of mating disruption, when applied to control P. versicolora.

Abstract

Age at mating is one of the most important factors that affect mating selection, sexual performance, and fecundity. We studied the effects of mating age on the mating performance and reproductive fitness of Plagiodera versicolora Laicharting, a serious pest of poplar and willow, by measuring the time from pairing to successful mating, mating duration, fecundity, hatching probability, and female lifespan. Delayed mating of females and males significantly prolonged the time from pairing to successful mating and the mating duration, but had no effect on the duration of the egg-laying period. Delayed mating of females did not significantly affect fecundity or egg hatching, but significantly prolonged the female lifespan. Although delayed mating of males had a significant negative impact on egg hatching, it had no effect on the lifespan or fecundity of females. These results indicate that delayed mating affects the mating performance of P. versicolora, although it has a limited effect on reproductive fitness. This suggests that delayed mating is unlikely to contribute to the success of mating disruption, when applied to control P. versicolora.

Sex and death

Sexual interactions negatively impact health and longevity in many species across the animal kingdom. C. elegans has been established as a good model to study how mating and intense sexual interactions influence longevity of the individuals. In this chapter, we review the most recent discoveries in this field. We first describe the phenotypes caused by intense mating, including shrinking, fat loss, and glycogen loss. We then describe three major mechanisms underlying mating-induced killing: germline activation, seminal fluid transfer, and male pheromone-mediated toxicity. Next, we summarize the current knowledge of genetic pathways involved in regulating mating-induced death, including DAF-9/DAF-12 steroid signaling, Insulin/IGF-1 signaling (IIS), and TOR signaling. Finally, we discuss the possible fitness benefits of mating-induced death. Throughout this review, we compare and contrast mating-induced death between the sexes and among different species in an effort to discuss this phenomenon and underlying mechanisms from the evolutionary perspective. Further investigation using mated C. elegans will improve our understanding of sexual antagonism, as well as the coordination between reproduction and somatic longevity in response to various external signals. Due to the evolutionary conservation in many aspects of mating-induced death, what we learn from a short-lived mated worm could provide new strategies to improve our own fitness and longevity.