Preferred males are not always good providers: female choice and male investment in tree crickets

Female tree crickets (Oecanthus nigricornis) prefer large males but do not receive larger glandular courtship gifts from these males. This finding is puzzling from both the male and female perspectives, because females should prefer males providing more direct benefits, and because males who provide larger gifts achieve higher insemination success. We tested for differences in the quality of male secretions and found that larger males provided more proteinaceous food gifts than did rivals, which could explain why they are preferred by females. The preference in turn could cause depletion of food gift reserves in favored males, because natural remating rates are high and because even a single feeding bout negatively affects glandular stores. Most intriguingly, we showed that preferred males can adaptively decrease the size of courtship food-gifts provided (in order to conserve gifts for future mating events) when they perceive that the probability of multiple future mating opportunities is high. Thus, the elevated mating rates of preferred males (both before and after a focal mating event) could account for the small size of their courtship food-gifts. Copyright 2005.