Thermal effect on the development and reproduction of an indigenous mirid bug, Pilophorus typicus Distant (Heteroptera: Miridae), a potential biological control agent in Japan

In order to establish the optimal thermal conditions for mass rearing of the predatory mirid bug Pilophorus typicus, we investigated the effect of temperature on the development and fecundity of this bug at 6 constant temperatures (17.5, 20.0, 22.5, 25.0, 27.5, and 30.0°C) under a 16L8D photoperiod. The developmental period of P. typicus from egg to adult at different temperatures was not affected by sex. The developmental zero (T₀) and thermal constant (K) of females from egg to adult were 12.0°C and 357.1 day-degrees, respectively. The corresponding values for males were 12.1°C and 357.1 day-degrees, respectively. The mean generation time (T) of P. typicus decreased with an increase in temperature from 17.5°C to 30.0^oC. Among the temperatures investigated, the net reproductive rate (R0) was highest at 25.0°C, whereas the highest intrinsic rate of natural increase (r_m) occurred at 27.5^oC. These results indicate that the optimal temperature for the mass rearing of P. typicus is between 25.0°C and 27.5^oC.