Time limitation affects offspring traits and female's fitness through maternal oviposition behaviour

Plasticity of various life-history traits has evoked continuing interest among biologists. For example, the plasticity of offspring characteristics as well as maternal effects may be affected by time limitation and by limitation caused by changing environmental conditions. However, it is difficult to tell apart the effect of a time constraint, experienced by the mother, from food limitation, which is experienced by the offspring at the end of the season. In this study, we controlled for food limitation and simulated a time constraint for the mother. We tested how the seed beetle, Coccotrypes dactyliperda, adapts its reproductive investment after encountering a period of low availability of seeds as oviposition sites, as compared with females that encountered a seed at an early adult stage, while maintaining a similar food supply for offspring of both groups. We show that time limitation has a significant effect on the reproductive investment patterns of females. Females that were prevented from ovipositing, but provided with abundant food and later given oviposition sites, produced more, but smaller offspring than control females. Although the number of offspring increased, there was no indication of competition for food between offspring. We propose that, in order to compensate for the loss of time, mothers that experienced a shortage of oviposition sites influence their offspring to mature faster at the cost of a smaller than average body size. This study emphasizes the importance of considering more than one offspring generation in order to correctly estimate female fitness.