Impact of maternal crowd on the reproductive performance of an ecto-pupal parasitoid Nesolynx thymus (Hymenoptera: Eulophidae)

Abstract

Int. J. Indust. Entomol. Vol. 29, No. (1), pp. 128-134 (2014) 128 129 thymus, 2 day-old N. thymus adults were provided with 3 dayold pupae of E. bombycis for parasitisation at host-parasitoid ratios of 1:1 to 1:10. The parasitoid adults were allowed to parasitize the host pupae for a period of 3 d when they were fed honey 50%. Thereafter, they were separated from the host pupae and the latter were kept for parasitoid emergence. Each treatment consisted of 10 replications. Following the emergence of the parasitoid progeny (first generation) number of pupae parasitized, developmental duration, sex-wise and total adult recovery, sex ratio, adult size and adult female longevity were recorded / calculated. Subsequently, the gravid female (2 day-old) emerging at different treatments (1:1 to 1:10) were offered four 3 dayold uzi pupae for parasitization for 3 d. After the emergence of parasitoid progeny (second generation) observations were recorded on the following: number of pupae parasitised, developmental duration, sex-wise and total adult recovery, and sex ratio. The longevity of first generation N. thymus females was determined by maintaining 10 replications each with 10 adults. The adults were fed honey 50% and their mortality was recorded at 24 h intervals. The size of the parasitoid adults was measured by selecting randomly 10 adults of each sex using an ocular micrometer at 40x. The results were analyzed statistically (SPSS Package) by one way ANOVA followed by DMRT for level of significance. Karl Pearson’s correlation co-efficients were also estimated to know the correlation between the ovipositing parasitoid density and reproductive as well as morphometric characteristics of N. thymus.