Life History and Size Structure of Larval Dragonfly Populations

Abstract

Comparative data on emergence, adult activity, and larval development were used to interpret patterns of phenology, voltinism, and developmental synchrony in a 14-species assemblage of dragonflies (Odonata:Anisoptera). Interspecific differences in these characteristics provided an opportunity to interrelate life history, population size structure, and the potential for intra- and interspecific interactions. Larval populations of most species comprised an extraordinary size range of individuals at any one time. In many species, this intraspecific size variability was primarily due to developmental asynchrony within generations (e.g., Libellula lydia, Celithemis elisa, Perithemis tenera). Oviposition in these species occurred throughout most of the summer so that the timing of instar development varied considerably among broods. By fall, the largest larvae in these populations were 5 to 10 times the size of smaller conspecifics. In other asynchronous breeders, an even wider size range of co-occurring conspe...