Gradient środowiskowy, a cechy ważek kluczowe w doborze naturalnym i płciowym

Dragonflies (Odonata), due to their wide geographic range and a variety of easily measurable traits, are excellent model organisms for ecological and evolutionary studies. It is possible to design experiments on dragonflies, both in laboratory and field settings, that take into account environmental gradients affecting natural and sexual selection in insects, which allows for the study of mechanisms associated with ongoing climate change. Studies on common beautiful demoiselle Calopteryx splendens examined whether its behaviours varied across geographically distant populations. The work showed that male activity increased with geographic latitude. Individuals from the northern species edge were the most bold, while males from the centre showed the greatest investment in courtship. The results suggest, among other things, that northern populations may actively colonize new areas. Other experiments conducted across the range gradient of the common spreadwing Lestes sponsa aimed to examine how latitude might influence sexual selection in this species. The results revealed that females from the centre of the species’ range were the most selective, and males from the north had the highest mating efficiency, which could affect the quality of offspring at the range margin. Laboratory experiments on the L. sponsa, inspired by earlier measurements of damselfly body traits in the field, aimed to check whether the evolutionary potential would differ along a latitudinal gradient (temperatures) among populations from distant regions. The results showed that damselflies from the north, experiencing the shortest season (time stress) and suboptimal temperature, exhibited the lowest additive genetic variation in the timing of egg hatching and the rate of larval growth, and the studied traits were strongly genetically linked. This means that populations at the range edge have the least ability to undergo evolutionary changes, and thus may have difficulties adapting to climate change. Including environmental gradients in ecological and evolutionary studies on insects appears to be crucial for obtaining results that bring us closer to understanding processes occurring in nature.