Twenty eight species of winter-active Heleomyzidae were collected during a long-term study in Poland. More than 130 samples of insects, including Heleomyzidae, were collected from the surface of snow in lowland and mountain areas using a semi-quantitative method. Lowland and mountain assemblages of Heleomyzidae recorded on snow were quite different. Heleomyza modesta (Meigen, 1835) and Scoliocentra (Leriola) brachypterna (Loew, 1873) dominated in the mountains, Tephrochlamys rufiventris (Meigen, 1830) mainly in the lowlands and Heteromyza rotundicornis (Zetterstedt, 1846) was common in both habitats. Heleomyzidae were found on snow during the whole period of snow cover, but the catches peaked from late November to the beginning of February. In late winter and early spring the occurrence of heleomyzids on snow decreased. Most individuals were active on snow at air temperatures between -2 and +2.5°C. A checklist of 78 winter active European Heleomyzidae is presented. Helomyza nivalis Wahlgren, 1918 is herein considered as a new junior synonym of Helomyza caesia Meigen, 1830, syn. n., Agnieszka Soszyńska-Maj, Andrzej J. Woźnica., and Obsahuje bibliografii
Water-filled tree holes are abundant microhabitats in forests worldwide and are inhabited by specialized communities of invertebrates. Despite their importance, the temporal dynamics of communities within and between years are largely unknown. Here, I present a case study on the phenology of insect larvae in two holes in a beech tree (lower and upper canopy) located in southern Germany over a period of three years. I asked whether water temperature and the characteristics of insect larvae at the community and population levels are similar in periodicity every year and whether they differ in the lower and upper canopy. The water temperature in tree holes differed greatly from air temperature, and this effect was more pronounced in the lower than in the upper canopy, which resulted in a lower probability of drying out occurring in the lower canopy. This was associated with a higher species richness in the lower canopy and greater abundance of drought tolerant species in the upper canopy. There was a significant periodicity in larval abundance, biomass, species richness and body size distribution of abundant species in both tree holes, but it was not seasonal. This result indicates that unpredictable drying out of tree holes are more important drivers of tree hole community dynamics than changes in water temperature. The community of larvae in the tree hole in the upper canopy lagged behind that in the lower canopy, which indicates that most species mainly colonize the more stable microhabitats in the lower canopy. Hopefully this case study will encourage future larger-scale phenological studies to test (1) whether the patterns observed in this study can be generalized over larger spatial scales and (2) the relative importance of abiotic and biotic drivers of the dynamics of communities in tree holes., Martin M. Gossner., and Obsahuje bibliografii