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
Climate change may facilitate shifts in the ranges and the spread of insect pests, but a warming climate may also affect herbivorous insects adversely if it disrupts the locally adapted synchrony between the phenology of insects and that of their host plant. The ability of a pest species to colonize new areas depends on its ability to adjust the timing of phenological events in its life cycle, particularly at high latitudes where there is marked seasonality in temperature and day length. Here we incubated eggs of three species of geometrid moth, Epirrita autumnata, Operophtera brumata and Erannis defoliaria from different geographical populations (E. autumnata and O. brumata from Northern Finland, E. autumnata and E. defoliaria from Southern Finland and all three species from Germany) in a climate chamber at a constant temperature to determine the relative importance of geographic origin in the timing of egg hatch measured in terms of cumulative temperature sums (degree days above 5°C, DD5); i.e. the relative importance of local adaptation versus phenotypic plasticity in the timing of egg hatch. In all three species, eggs from northern populations required a significantly lower temperature sum for hatching than eggs from southern populations, but the differences between them in temperature sum requirements varied considerably among species, with the differences being largest for the earliest hatching and northernmost species, E. autumnata, and smallest for the southern, late-hatching E. defoliaria. In addition, the difference in hatch timing between the E. autumnata eggs from Southern Finland and Germany was many times greater than the difference between the two Finnish populations of E. autumnata, despite the fact that the geographical distances between these populations is similar. We discuss how these differences in hatching time may be explained by the differences in hatch-budburst synchrony and its importance for different moth species and populations. We also briefly reflect on the significance of photoperiod, which is not affected by climate change. It is a controller that works parallel or in addition to temperature sum both for egg hatch in moths and bud burst of their host plants., Julia Fält-Nardmann, Tero Klemola, Mechthild Roth, Kai Ruohomäki, Kari Saikkonen., and Obsahuje bibliografii
There is much current discussion about the factors that control the distribution and abundance of animal species, particularly at the edges of their range. The significance of temperature for survival and development is compared in two closely related psyllid species (Craspedolepta nebulosa and C. subpunctata) living on the same host plant (Chamerion angustifolium) (Onagraceae) but displaying different distributions along latitudinal and altitudinal gradients. The following measurements were made at critical periods during the life cycle (a) winter supercooling points (SCPs), (b) tolerance of short (1 min) and long term (1-25) days exposure to sub-zero temperatures above the SCP, (c) tolerance of short term exposure to high spring/summer temperatures and (d) comparative field development rates among species and sites during the early critical part of the growing season. Successful completion of the life cycle is related to heat availability during the growing season. This appears to limit the distribution of the Craspedolepta species, rather than their survival response to thermal extremes. No significant differences were found between the two species in the supercooling point or in their long and short term survival responses at low or high temperatures., Jeremy M. Bird, Ian D. Hodkinson, and Lit