Relationships between morphological characters and fitness components in three close populations of Lestes barbarus (Odonata: Lestidae).

Survival and mating success are two components of fitness that have often been often thought to be related with several individual characteristics. Among these SIZE and Fluctuating Asymmetry are the most frequently investigated, and many studies have been done on adult Odonata, because of their well known behaviour and the facility with which they can be observed, caught and measured. We investigated these relationships in three close populations of another odonate species, Lestes barbarus, whose longer pre-reproductive period allows the time for the selection to act, and whose philopatry allows us to measure the effect. Furthermore, we also investigated relationships between male mating success and SIZE, FA, thorax and total weights and their ratio. Our results have shown that there were no uniform effects of the selection on the three populations, but there were different effects on some of these: stabilizing, disruptive and directional selection. These results show that the morphological characteristics can affect natural selection in different ways even in populations very close to each other and in apparently similar environmental conditions. This might explain why a lot of studies on relationships between SIZE, FA and fitness performances, usually done on a single population, have so often given contrasting results.