Abstract
The seasonal life cycle of the house spider, Achaeranea tepidariorum, was investigated in the field at Hirosaki, Aomori prefecture. Spiders of all nymphal instars and adults were found throughout the year and the overwintering stage was not restricted to a particular developmental stage. The reproductive activity occurred for a long period of time from June to October. The seasonal occurrence of adult males, the egg laying pattern and its geographical variation suggested that in spite of such life cycle characteristics, this species is basically univoltine throughout Japan. The variability of its overwintering stage may have evolved in association with the scattered emergence of the spiderlings over a long period of time.
