Geographical and annual variations in the phenology of some terrestrial isopods (Isopoda, Oniscidea)

Three species of terrestrial isopods (Isopoda, Oniscidea), Ligidium hypnorum (Ligiidae), Trachelipus rathkii (Trachelipodidae) and Armadillidium opacum (Armadillidiidae), were observed in 1993 concerning their breeding phenology in different sites in south-western Germany. We compared the resulting phenology patterns to data discussed in the literature. Furthermore, annual and geographical variations in the reproductive period were examined using data from woodlice collected in the nearby national preserved area ''Federsee'' in 1987. Clear interspecific differences in the duration of the reproductive time interval were ol,served. On the other hand, within the examined area geographical variations in the phenology of the investigated species appeared to he rather small, while remarkable annual changes occurred concerning the beginning of the breeding period. We discuss the influence of changes in climatic factors on breeding phenology of terrestrial isopods. Furthermore, we show patterns that describe the annual phenology of the observed species.