Drosophila melanogaster is a suitable model for investigating how neuropeptides influence animal behaviours and physiology. We previously reported that two behavioural paradigms control mating duration of male Drosophila, called Longer-Mating-Duration (LMD) andShorter-Mating-Duration (SMD) that are induced through socio-sexual environment prior to copulation. Understanding the molecular and cellular mechanisms by which males exhibit plasticity to different social cues remains poorly understood. Here, we show that SIFa modulates the neural circuitry for both LMD and SMD. Neuropeptide-to-neuropeptide communication, so called 'neuropeptide relay' plays a key role to mediate this control. We identified that 7 neuropeptides expressed in SIFa Receptor-positive cells are functionally important to regulate either LMD and/or SMD. The modulation of two independent mating duration behaviour by the different SIFa-mediated neuropeptide relay will help to further investigate how the neuropeptidergic modulation can control complex behaviours.

Males have finite resources to spend on reproduction. Thus, males rely on a ‘time investment strategy’ to maximize their reproductive success. For example, male Drosophila melanogaster extends their mating duration when surrounded by conditions enriched with rivals. Here we report a different form of behavioral plasticity whereby male fruit flies exhibit a shortened duration of mating when they are sexually experienced; we refer to this plasticity as ‘shorter-mating-duration (SMD)’. SMD is a plastic behavior and requires sexually dimorphic taste neurons. We identified several neurons in the male foreleg and midleg that express specific sugar and pheromone receptors. Using a cost-benefit model and behavioral experiments, we further show that SMD behavior exhibits adaptive behavioral plasticity in male flies. Thus, our study delineates the molecular and cellular basis of the sensory inputs required for SMD; this represents a plastic interval timing behavior that could serve as a model system to study how multisensory inputs converge to modify interval timing behavior for improved adaptation.

Males have finite resources to spend on reproduction. Thus, males rely on a 'time investment strategy' to maximize their reproductive success. For example, male Drosophila melanogaster extends their mating duration when surrounded by conditions enriched with rivals. Here we report a novel form of behavioral plasticity whereby male fruit flies exhibit a shortened duration of mating when they are sexually experienced; we refer to this plasticity as 'shorter-mating-duration (SMD)'. SMD is a plastic behavior and requires sexually dimorphic taste neurons. We identified several neurons in the male foreleg and midleg that express specific sugar, pheromone and mechanosensory receptors. Using a cost-benefit model and behavioral experiments, we further show that SMD behavior exhibits adaptive behavioral plasticity in male flies. Thus, our study delineates the molecular and cellular basis of the sensory inputs required for SMD; this represents a plastic interval timing behavior that could serve as a model system to study how multisensory inputs converge to modify interval timing behavior for improved adaptation.

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