Post-Mating Responses in Insects Induced by Seminal Fluid Proteins and Octopamine

SIMPLE SUMMARY: During insect mating, male insects trigger post-mating responses in females through seminal fluid proteins, inducing a physiological transition in females that is conducive to reproduction. Simultaneously, this process indirectly increases the male’s chances of producing offspring through competition. Females, on the other hand, elicit short- and long-term post-mating responses through proteins and neural networks. Within the intricate regulatory network, seminal fluid proteins and octopamine play pivotal roles. The network spans from the female’s reproductive organs and abdominal ganglion to the brain and operates by activating receptors for seminal fluid proteins and octopamine. This activation leads to the modulation of various signals, influencing the female’s physiological behavior, organ structure, and hormone secretion, and facilitating enhanced nutrient intake, increased expression of reproductive-related genes, ovulation, and sperm storage. Ultimately, these processes aid in the successful oviposition of females. ABSTRACT: Following insect mating, females often exhibit a series of physiological, behavioral, and gene expression changes. These post-mating responses (PMRs) are induced by seminal fluid components other than sperm, which not only form network proteins to assist sperm localization, supplement female-specific protein requirements, and facilitate the formation of specialized functional structures, but also activate neuronal signaling pathways in insects. This review primarily discusses the roles of seminal fluid proteins (SFPs) and octopamine (OA) in various PMRs in insects. It explores the regulatory mechanisms and mediation conditions by which they trigger PMRs, along with the series of gene expression differences they induce. Insect PMRs involve a transition from protein signaling to neuronal signaling, ultimately manifested through neural regulation and gene expression. The intricate signaling network formed as a result significantly influences female behavior and organ function, contributing to both successful reproduction and the outcomes of sexual conflict.