Emergence patterns and latitudinal adaptations in development time of odonata in north Sweden and Poland

Abstract

Using exuviae, data are presented on emergence dates of dragonflies from northernSweden and northwestern Poland. The 17 spp. sampled in Sweden showed considerableoverlap in emergence periods. In Sweden, Leucorrhinia rubicunda was thefirst sp. to emerge (May 31) and Sympetrum danae the last (July 19). A comparison offirst dates of emergence of spp. in Sweden and Poland showed a difference between 9and 30 days, with all Polish spp. emerging first. Compared to spring species, summerspecies and obligate univoltine summer species showed less difference in first date ofemergence between Swedish and Polish populations. In a laboratory experiment Leucorrhiniadubia was reared from both regions from the egg to final instar larva undernorthern Swedish and northwestern Polish photoperiods. Swedish larvae developedfaster under a northern Swedish photoperiod compared to a northwestern Polish photoperiod.However, no such difference in development was found for northwesternPolish larvae. This suggests that there are genetic differences between both populationsin response to photoperiod. The results are discussed in the context of compensationof larval development of northern populations in relation to photoperiod