A pleiotropic chemoreceptor facilitates the functional coupling of pheromone production and perception

Optimal mating decisions depend on the robust coupling of signal production and perception because independent changes in either could carry a fitness cost. However, since the perception and production of mating signals are often mediated by different tissues and cell types, the mechanisms that drive and maintain their coupling remain unknown for most animal species. Here, we show that in Drosophila, sensory perception and production of an inhibitory mating pheromone are co-regulated by Gr8a, a member of the Gustatory receptor gene family. Specifically, we found that the pleiotropic action of Gr8a independently regulates the perception of pheromones by the chemosensory systems of males and females, as well as their production in the fat body and oenocytes of males. These findings provide a relatively simple molecular explanation for how pleiotropic receptors maintain robust mating signaling systems at the population and species levels.

Genome-Wide Identification of the Gustatory Receptor Gene Family of the Invasive Pest, Red Palm Weevil, Rhynchophorus ferrugineus (Olivier, 1790)

The red palm weevil (Rhynchophorus ferrugineus) is a highly destructive pest of oil palm, date, and coconut in many parts of Asia, Europe, and Africa. The Food and Agriculture Organization of the United Nations has called for international collaboration to develop a multidisciplinary strategy to control this invasive pest. Previous research focused on the molecular basis of chemoreception in this species, particularly olfaction, to develop biosensors for early detection and more effective bait traps for mass trapping. However, the molecular basis of gustation, which plays an essential role in discriminating food and egg-laying sites and chemical communication in this species, is limited because its complete gustatory receptor gene family still has not been characterized. We manually annotated the gene family from the recently available genome and transcriptome data and reported 50 gustatory receptor genes encoding 65 gustatory receptors, including 7 carbon dioxide, 9 sugar, and 49 bitter receptors. This study provides a platform for future functional analysis and comparative chemosensory study. A better understanding of gustation will improve our understanding of this species’ complex chemoreception, which is an important step toward developing more effective control methods.