Consequences of Larval Ecology for Territoriality and Reproductive Success of a Neotropical Damselfly

Abstract

Male territorial behavior and female oviposition behavior of Megaloprepus coerulatus, a damselfly that develops in water—filled tree holes, is interpreted in light of its larval ecology. Sexual selection favors large males because they win more territorial contests than do smaller males, and females mate only in the vicinity of defended tree holes (i.e.,passive female choice). Small males behave as territory holders until displaced, and/or act as subordinate satellites at large territories. Females are more predictably found in forest light gaps, even though they oviposit in both gap and understory tree holes. Males defended only 14% of the sites used by ovipositing females. Large tree holes are relatively rare, but support a greater number of emerging adults per season and produce larger adults than tree holes containing ≤1 L of water, which rarely produce more than one individual per season. By defending only large tree holes in gap areas, a male increases his chances of mating, and of producing multiple offspring and reproductively successful sons. Results from a field experiment suggest that both mate acquisition and procurement of superior larval habitats have been selective pressures in the evolution of male territory choice. Because even large holes are inadequate to support a female's entire clutch, and the presence of conspecific and heterospecific odonate larvae makes offspring survival uncertain, selection favors a female that partitions her clutch among multiple tree holes.