Seasonal Changes in the Incidence of Embryonic Diapause in the Band-Legged Ground Cricket, Dianemobius nigrofasciatus

Abstract

Abstract The incidence of embryonic diapause in the band-legged ground cricket, Dianemobius nigrofasciatus was examined in regard to egg production by individual females both in the laboratory and in the field in Osaka, Japan. (1) Females were classified into three types: diapause egg-producers (laid only diapause eggs), nondiapause egg-producers (laid only nondiapause eggs) and mixed egg-producers (laid both diapause and nondiapause eggs). (2) The longer the photophase, the smaller was the incidence of diapause egg-producers, and the larger was that of the nondiapause egg- and mixed egg-producers. The critical day-length was between 13 and 14 hr. (3) The longer the photophase, the smaller was the incidence of diapause eggs laid by mixed egg-producers. (4) In the field, both nondiapause egg-producers and mixed egg-producers were observed from June to August. In September and October, most of the females were diapause egg-producers. The present findings revealed that adults of the overwintered generation o...