An investigation on the recolonization and population dynamics of the Redback spider (Latrodectus hasseltii) was conducted bimonthly at a seaside park in Kaizuka City, Osaka, Japan, after all the spiders were completely removed from the study area in December 2000. The Redback spiders invaded again in February 2001, and their population density was recovered in December 2001. This study confirmed that breeding of Redback spiders began in June and continued until December.The minimum population observed in June was composed of only adult female individuals, while the maximum population found in December 2001 mainly consisted of larvae. The prolonged breeding might have caused the increase of population density and dispersal. The temperature measured ranged from -0.5℃ to 46.1℃ ; however. the Redback spider tolerated this harsh environment. This confirmed that the Redback spider, a tropical or subtropical species, is capable of colonizing even in the temperate area in Japan.
