Cellular and molecular components regulating social behaviour of male Drosophila

Abstract

Environmental conditions, such as the socio‐sexual context, can change rapidly. In these circumstances, the ability of animal of a genotype to express a different phenotype according to the environment can improve survival and reproductive success. A primary function of males for many species involves mating with females for reproduction. For males, current mating investment can often be subject to trade‐offs with future mating opportunities to maximize fitness in a rapidly changing socio‐sexual environment. Males have a finite resource for reproduction; hence a ‘time investment strategy’ has evolved to maximize reproductive success. Drosophila males respond to the presence of rivals by prolonging mating duration to increase the chance of passing on genes. In previous studies, we examined the genetic network and neural circuits that regulate rival‐induced longer mating duration (LMD). LMD can be induced solely via visual stimuli. LMD depends on the circadian clock genes timeless and period, but not Clock or cycle. LMD involves the memory circuit of the ellipsoid body (EB). Further, we identified a small subset of clock neurons in the male brain that regulate LMD via neuropeptide signaling.More recently, we investigated a novel behavioral plasticity whereby male fruit flies exhibit a shortened mating duration when sexually satiated, called ‘Shorter‐Mating‐Duration (SMD)’. Both sexual experiences and contact‐based chemoreception is necessary to induce SMD. SMD requires the sexually dimorphic Gr5a‐positive neurons to detect female body pheromones, and can be induced by gustatory stimuli. The memory circuitry within the ellipsoid body (EB) and mushroom body (MB) brain regions is crucial to process this satiety state. SMD depends on the circadian clock genes Clock and cycle, but not timeless or period. SMD also relies on signaling via the neuropeptide sNPF, but not PDF or NPF. Sexual experience modifies the neuronal activity of a subset of sNPF‐positive neurons involved in neuropeptide signaling, which modulates SMD. Thus, our study delineates the molecular and cellular basis for SMD – a plastic social behavior that can be modified by sexual experience.Our studies delineate part of the molecular and cellular basis of plastic behaviors elicited by different socio‐sexual environments. LMD together with SMD can be a model to study how the socio‐sexual environment affects on male behavioral plasticity via neural circuitry.Support or Funding InformationHHMINIH R01University of Ottawa Startup grant