Neuropeptide Modulation that Switches the Mating Decision of the fruit fly Drosophila melanogaster Female
  • Young-Joon Kim Ph.D
  • SLS Colloquia / Oct 25th 04:00 / BLDG.110 ROOM N104
Abstract

Decision-making circuits and pattern generators are often multi-functional, and neuromodulators such as monoamines and neuropeptides configure their states of excitability. The circuitry by which females decide whether to accept or reject the male courtship can also switch between two opposing states; mating-permissive and ?refractory. In Drosophila, a seminal protein sex peptide (SP) is responsible for the reversible switch and triggers long-term mating-refractoriness (LTMR). Upon transfer, SP acts on SPR-positive sensory neurons (SPSN) in the ovary, and SPSN relays the SP signal to SAG that projects to the dorsal brain. However, the brain circuit downstream of SAG remains unknown. Here, we show a neuropeptide diuretic hormone 44 (Dh44) and its receptor Dh44-R1 are critical for the production of the SP-induced LTMR. The virgin females that lack Dh44 or Dh44-R1 show the low mating receptivity reminiscent to LTMR, whereas the mated females with elevated Dh44 signaling show no LTMR even after mating. The SP signal from SAG seems to feed into two pairs of specific brain Dh44 neurons linked with pC1, a brain processor of male-courtship signals. Our data suggest that the Dh44-Dh44R1 pathway switches functional states of pC1 and mating motivation. Since orthologs of Dh44 and Dh44R1 occur in mammals, it is interesting to examine degrees of conservation in their functions in the female mating behavior.