Regulation of fecundity, progeny production and female-male composition of Bracon Brevicornis Wesmael (Hymenop Tera : Braconidae)

Abstract

The fecundity, progeny production, female-male ccmposition offhe progeny of Bracon brevicorn/s Wesmael as influenced b/ density and weight of host larvae of Corcyra caphalonica Stainton and the sex-ratio of the parent parasite population were studied at three temperature-humidity combinations, namely, 28°C-75% RH (TH,), 30aC-60% RH (THJ and 32°C-50% RH {TH3) • The effect of the main factors on parasite development was found to be modified by the temperature humidity conditions of rearing. The maximum fecundity of the parasite was registered consistently at all the three TH levels at a host density level of two larvae per female parasite and when the parental parasite sex ratio was kept at 2.1 and 3:1 (femalermale). The highest progeny production was attained at the THt and TH^ levels under a host density le/e! of two heavie' (30-35 mg) larvae per female parasite, The influence of host larva! density on the proportion of females was pronounced only at the TH^ level and a density of two larvae per female parasite was found to be better for the production of higher proportion of females. The parental sex-ratios of 1:3 (female : male) produced higher proportion of females at the THLJ and TH3 levels.