The breeding biology of the common redstart, Phoenicurus phoenicurus, was studied from 295 nests over 20 years in a nest-box population breeding in managed pine forest in the northeast of the Czech Republic, central Europe. The laying of first eggs lasted from 30 April until 30 June with two distinct peaks in May and June. The estimated proportion of pairs producing two broods per season was 65.4%, the highest estimate in studies of this species. Nest success was only 45.1%, one of the lowest known values. The mean clutch size was 6.30 eggs in assumed first broods and 5.39 eggs in assumed second broods. The production of two broods per season and relatively small clutches is probably a parental adaptation to conditions of frequent nest predation. The two breeding attempts per season could not, however, compensate for the latitudinal differences in clutch size and breeding success, and the seasonal breeding productivity was lower in comparison to populations in the northern area of distribution. At higher air temperatures the breeding started earlier. The air temperature also affected nest success which was highest at mean temperature values and decreased to both low and high temperature extremes. The effects of precipitation, first-egg-laying date, clutch size and year of observation on nest success were not significant.
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