Abstract
The powers of survival of 4 species of cockroaches under a low temperature of 5.5±0.5℃ were investigated. No any stage of Periplaneta americana and Blattella germanica could tolerate the chilling treatment of 40 days. Nymphs of older instars of P. fuliginosa survived for 90 days and some oothecae for more than 80 days under the chilling treatment, when given an exposure to 15±1℃ beforehand. Most of nymphs and adults of P. japonica tolerated the chilling treatment for more than 90 days with the preliminary exposure. These results suggest that P. americana and B. germanica hardly survive the coldest 3 months outdoors or in unheated buildings in Central Japan, whereas P. fuliginosa and P. japonica tolerate the winter under outdoor conditions.
