Sex specific molecular responses of quick-to-court protein in Indian malarial vector Anopheles culicifacies : conflict of mating versus blood feeding behaviour

Abstract

Understanding the molecular basis of mosquito behavioural complexity plays a central role in designing novel molecular tools to fight against their vector-borne diseases. Although the olfactory system plays an important role in guiding and managing many behavioural responses including feeding and mating, but the sex-specific regulation of olfactory responses remain poorly investigated. From our ongoing transcriptomic data annotation of olfactory tissue of blood fed adult female <i>An. culicifacies</i> mosquitoes; we have identified a 383 bp long unique transcript encoding a <i>Drosophila</i> homolog of the quick-to-court protein. Previously this was shown to regulate courtship behaviour in adult male <i>Drosophila</i>. A comprehensive <i>in silico</i> analysis of the <i>quick-to-court</i> (<i>qtc</i>) gene of <i>An. culicifacies</i> (<i>Ac-qtc</i>) predicts a 1536 bp single copy gene encoding 511 amino acid protein, having a high degree of conservation with other insect homologs. The age-dependent increased expression of putative <i>Ac-qtc</i> correlated with the maturation of the olfactory system, necessary to meet the sex-specific conflicting demand of mating (mate finding) versus host-seeking behavioural responses. Sixteen to eighteen hours of starvation did not alter <i>Ac-qtc</i> expression in both sexes, however, blood feeding significantly modulated its response in the adult female mosquitoes, confirming that it may not be involved in sugar feeding associated behavioural regulation. Finally, a dual behavioural and molecular assay indicated that natural dysregulation of <i>Ac-qtc</i> in the late evening might promote the mating events for successful insemination. We hypothesize that <i>Ac-qtc</i> may play a unique role to regulate the sex-specific conflicting demand of mosquito courtship behaviour versus blood feeding behaviour in the adult female mosquitoes. Further elucidation of this molecular mechanism may provide further information to evaluate <i>Ac-qtc</i> as a key molecular target for mosquito-borne disease management.