Effect of temperature on development of Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae) parasitizing larvae of the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) in brown rice

Abstract

The development and adult longevity of Theocolax elegans (Westwood) were investigated at six temperatures (20, 25, 28, 30, 32 and 35°C), 70–80% RH and a 16L–8D photoperiod. Fecundity was also investigated at 25°C and 30°C. The hosts were larvae of Sitophilus zeamais Motschulsky reared on brown rice. As the temperature was increased from 20°C to 32°C, the developmental period decreased from 54.4 to 16.2 days for females and from 53.8 to 15.6 days for males. The developmental period at 35°C was longer than at 32°C. Males developed faster than females. Adult longevity decreased with increasing temperature from 14.5 to 4.5 days for females and from 20.6 to 3.6 days for males. The mean number of progeny produced per female over a lifetime was 161.0 at 25°C and 110.1 at 30°C. The intrinsic rate of natural increase (rm) was 0.131 females per female per day at 25°C and 0.169 females per female per day at 30°C.