The tolerance of Latrodectus hasseltii (Araneae : Theridiidae) to low temperatures

Abstract

The redback spider (Latrodectus hasseltii) collected in Osaka Prefecture tolerated well sub-zero temperatures. Life and death of spiderlings and adults were observed in temperatures varied from 4 to -10.5℃. Among them, the male adults showed the best tolerance, with 50% survival during 30min. at around -10℃, followed by the second-instar spiderlings 30% of which were able to survive 25min. at the same temperature. This indicates the possibility of further expansion and habitation of the redback spider in colder climates in Japan.