ENVIRONMENTAL ASPECTS OF THE SURVIVAL AND REPRODUCTION OF ORIENTAL COCKROACHES (BLATTA ORIENTALIS L.).

Abstract:
The ability of mobile stages of oriental cockroaches to survive at -5C increased with acclimation at 10°C. Fully acclimated insects had LT5Os (time) of 1.3 - 4.1 days, depending on stage. A minimum of 8 days at - 5°C or 1 days at - 10°C was required to kill all stages; insects could survive for more than 6 weeks at 2C. The critical temperature for continued oothecal production by females and for hatch of oothecae lay between 15C and 20C. Females prevented from depositing oothecae by cold exposure rapidly resumed production when returned to a preferred temperature (28°C). Incubation times for oothecae were independent of relative humidity (RH) over the range 20-28°C; mean times to hatch were 42.7 days, 60.7 days and 89.3 days at 28C, 24C and 20C respectively. The mean number of nymphs emerging from oothecae decreased with RH within this temperature range.