SEX AND HABITAT DIFFERENCES IN FEEDING BY AN ADULT DAMSELFLY

Adult male and female Enallagma boreale (Zygoptera: Coenagrionidae) differ in mass at sexual maturity but not at emergence. This could be the result of differential feeding behaviour or allocation of resources. To separate these two possibilities animals were collected on six dates over the course of one flight season. Collections were made at a pond where reproduction occurs and on an adjacent hillside. Females had on average 25% more in their guts than did males. Both males and females away from the pond had more in their guts than those at the pond. Among males at the pond there was no difference in mean gut contents between mated and unmated individuals. The risk-sensitivity of foraging in many animals suggests that it is inherently dangerous. Differences in foraging rate as described here could result in differences in mortality rates that would change population sex ratios and ultimately mating systems.