Causes and consequences of variation in female mating frequency in the almond moth, Cadra cautella

Abstract

Variation in male mating success is an important mechanism driving sexual selection, while variation in female mating frequency typically receives less attention. We examined this variation in female mating frequency in the almond moth, Cadra cautella. First, we measured female mating frequency under a variety of population sizes and sex ratios. Second, we allowed females to mate either once only, ad libitum with the same male, or ad libitum with novel males. We found larger females tended to copulate more often, and females mated more frequently in male-biased environments. Furthermore, females mated more frequently when exposed to multiple novel males than when exposed to a single male, either once or repeatedly. Female fecundity was not affected by her mating frequency, but females housed with novel males laid fewer eggs than females housed continuously with the same male, indicating a potential cost of male courtship. Finally, females that mated more frequently and laid more eggs survived significantly longer. The potential factors driving this variation in female mating frequency in the absence of any clear costs or benefits are discussed.