Evidence of a random ovipositional strategy by female fruit fly Bactrocera dorsalis (Tephritidae: Diptera) with reference to host quantum.
Abraham Verghese, Uma M. S., Jayanthi P. D. K., Ranju Mouly, Mahiba Helen
Author Affiliation: Indian Institute of Horticultural Research, Hessarghatta Lake PO, Bangalore 560 089, India.
Current Science 100 : 246-249
Abstract : Mango (Mangifera indica L.) is a favoured host of the fruit fly, Bactrocera dorsalis (Hendel), on which the females oviposit. Detailed laboratory studies were carried out to study the role of host biomass (=weight) on the oviposition decision of the tephritid fruit fly, B. dorsalis. The hypothesis that the biomass of mango fruit influences the decision of the mother (=gravid) fruit fly was tested on three varieties, Alphonso, Totapuri and Banganpalli, in three different but identical experiments. The results clearly showed that the number of oviposition punctures by a female fruit fly did not show significant differences among the different weight groups within a variety. The correlation coefficients between fruit weight and number of oviposition punctures were also not significant, i.e. the weight of the fruit did not influence the number of ovipositional punctures by the female fruit flies. This was true in all the three varieties. Further, the fruit weight did not influence the number of pupae that metamorphosed, number of adults that emerged and sex ratio in all the three experiments. The implications of these results on oviposition selection strategy of the female fruit fly are discussed. The study clearly indicated that after selecting a host (mango) the female fruit fly does not show non-random selection for a mango fruit with more quantum of pulp, as is expected if it were to maximize its survival and fitness.