Effects of temperature of adults and eggs on the induction of embryonic diapause in the band‐legged ground cricket, Dianemobius nigrofasciatus

Abstract

Abstract Eggs laid by adult female Dianemobius nigrofasciatus, reared under long‐day (LD 16 : 8 h, 25 °C) or short‐day (LD 12 : 12 h, 25 °C) conditions from the nymphal stage, are kept at several constant temperatures. At 22.5–30.0 °C, eggs laid by long‐day adults show lower incidences of diapause than those laid by short‐day adults. In both eggs laid by adults under long‐day conditions and those under short‐day conditions, the higher the temperature at which the eggs are kept, the lower the incidence of diapause. When eggs of long‐day adults are exposed to a low‐temperature pulse (10 °C, 24 h) on the day of deposition (day 0), the incidence of diapause increases. The low‐temperature pulse on day 1 does not increase the incidence of diapause. By contrast, when the eggs of short‐day adults are exposed to a high‐temperature pulse (35 °C, 24 h) on day 0 or day 1, the incidence of diapause decreases. The temperature pulses on day 0 are more effective at diapause prevention. Staining of diapause eggs by the Feulgen–Rossenbeck method shows that the eggs enter diapause at the blastoderm stage, which is on day 1 or day 2 at 25 °C. The exposure of adults to long days and higher temperatures prevents the eggs from entering diapause. In D. nigrofasciatus, embryonic diapause is controlled by maternal effects, adult photoperiod and temperature, and egg temperature before or at diapause.