The Influence of Body Size and Agility in Displacement Capacity of Male Damselflies (Odonata, Protoneurinae)

Abstract

Alternative mating tactics (AMT) occur in several animal taxa as a way to respond to physiological or environmental factors that affect reproductive success. In other words, males can exhibit different mate acquisition tactics associated with phenotypic variations. Here we present the case of Epipleoneura williamsoni, a non-territorial Neotropical damselfly in which larger males actively search for females along the margins of streams and smaller males remain perched on the vegetation and adopt a sit-and-wait strategy. Males were captured, marked and behavioral observations were conducted to take notes on the spatial displacement of individuals. We then measured male body size and agility to test whether these traits could be used to predict flight ability and thus AMT’s. Agility was measured by the ȓ2(S) coefficient, which is a surrogate of flight ability and maneuverability. The results show that body size was positively correlated with male flight ability and agility. However, male agility did not predict the adopted AMT. These results suggest that the strategies adopted by E. williamsoni males may be a reflection of body condition. This study adds evidence on how selection may act on different phenotypes within a population and how body size variations may result in different displacement capacities and flight agility.