Fitness Consequences of Multiple Mating on Female Sitophilus oryzae L. (Coleoptera: Curculionidae)

The effects of multiple mating on Þtness in the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), were studied. In the Þrst of a series of experiments, the impact of multiple mating on female Þtness was determined by evaluating the effects of a single mating period with one male, continuous exposure to one male, and continuous exposure to Þve males. Continuous exposure to one male increased lifetime fecundity by extending the period of time progeny were produced compared with a single mating period with one male, although average progeny size was reduced. Exposure to Þve males signiÞcantly reduced female survival and the number and size of progeny produced compared with the other treatments. In the second experiment, the number of progeny and the length of time progeny could be produced froma single copulationwere determined. Females became sperm depleted within 7 1 wk after laying 259 22 progeny, but a second mating period 9 wk after the Þrst copulation extended progeny production. In the Þnal experiment, the mechanism for thedecline inprogenyproduction at highmaledensitieswasdetermined tobe reduced oviposition, caused at least in part by a high proportion of time spent in copula. The number of copulations has costs and beneÞts for females that may affect population dynamics.