Mating stimuli cause dramatic changes in the female tsetse fly (Glossina morsitans) reproductive tract at the levels of gene expression, biochemistry and morphology

Tsetse flies (Glossina sp.) transmit the human and animal forms of African Trypanosomiasis, neglected diseases, which affect marginalized populations in sub-Saharan Africa. Tsetse flies have low reproductive capacity and low population numbers relative to other disease vectors as they reproduce by obligate viviparity (intrauterine larval development/nutrition and live birth). This work investigates the physiological response by female tsetse flies to mating stimuli. Mating stimuli and male seminal fluid proteins, induce physiological and behavioral changes observed in mated female insects. In Glossina, these include reduced receptivity to remating, increased blood meal volume and initiation of ovulation. Time course analysis of the post mating response by tsetse fly females by gene expression, metabolomic and morphological analyses of female reproductive tissues reveal significant changes in gene expression patterns, metabolite abundances, and morphological shifts over a 72-hour time course after mating. The transcriptional response peaks at 24 hours post mating and is distinguished by the dramatic increase in transcripts encoding a female reproductive specific OBP, orthologs of royal jelly protein in bees (responsible for initiation of developmental programs resulting in queen development from workers), and upregulation of structural, transporter, calcium signaling and stretch reception genes. Metabolomic analyses reveal increases in phospholipid moieties likely derived from the male seminal secretions which may function as a nuptial gift. These analyses reveal an array of new insights into the physiology of the post-mating response in Glossina which will be the focus of targeted research to identify processes with potential as targets for reproductive inhibition.