Clock-related neuropeptides in

Introduction: The pea aphid ( Methods: Here, we characterized the complete set of neuropeptides in the aphid brain and, using a combination of transcriptomic and peptidomic approaches, and investigated the neuropeptides expressed in the circadian clock neurons using immunohistochemistry. Results: We confirmed a large number of peptides, including several peptides described for the first time in this species. Furthermore, we found that circadian clock neurons express a variety of these neuropeptides, some of which overlapped within the same clock neuron type. In the lateral clock neurons, we found Pigment-Dispersing Factor, FMRFamide, Orcokinin a and Allatotropin, a neuropeptide profile that closely resembles that of cockroach clock neurons but differs markedly from that of the fruit fly, with the exception of Pigment-Dispersing Factor. In dorsal clock neurons, which are homologous to those that are presynaptic to insulin-producing cells in Discussion: Together, our findings provide the first comprehensive map of neuropeptides associated with the pea aphid circadian clock, offering new insights into how clock neurons may regulate seasonal responses and establishing a foundation for future functional studies of neuropeptide-mediated photoperiodism.