Temperature dependence of flight activity of odonata by ponds

The relationship between the onset and the level of odon. flight activity and ambient temperature (T-a) was investigated at mating sites mainly in northern Germany, but also in southern France. Several spp. were able to fly at lower T-a at the mating site in September than in June and July. The level of flight activity depended on T-a. In summer, Ischnura elegans (Zygoptera) and Orthetrum cancellatum (Anisoptera), could fly at the lowest T-a and exhibited special warming-up strategies. Southern spp. started activity at the mating site at higher T-a than did northern spp.