Endogenous corazonin signaling modulates the post-mating switch in behavior and physiology in females of the brown planthopper and Drosophila

Mating in insects commonly induces an alteration in behavior and physiology in the female that ensures optimal offspring. This is referred to as a post-mating response (PMR). The induction of a PMR requires not only male-derived factors transferred with semen during copulation, such as sex peptide (SP) in Drosophila , but also intrinsic female signaling components. The latter signaling remains poorly understood in most insects, including the brown planthopper (BPH) Nilaparvata lugens , a devastating rice pest. In BPHs the PMR comprises a reduced receptivity to re-mating and increased oviposition. Here, we demonstrate that the neuropeptide corazonin (CRZ) and its receptor (CrzR) are critical for the PMR in female BPHs. Peptide injection and knockdown of CRZ expression by RNAi or CRISPR/Cas9-mediated mutagenesis demonstrate that distensible CRZ signaling suppresses mating receptivity in virgin N. lugens females and mediates a reduction in re-mating frequency and increased ovulation. The CrzR is highly expressed in the female reproductive tract, and CrzR -knockdown phenocopies Crz diminishment. Importantly, female CRZ/CrzR signaling is indispensable for male seminal fluid factors (e.g. maccessin) to induce the PMR. With disrupted CrzR signaling, seminal fluid or maccessin injection fails to reduce female receptivity. Notably, CRZ is not produced in male accessory gland (MAG) and thus not transferred during copulation. However, male Crz knockout impairs the PMR in mated females and combining male and female Crz knockouts nearly abolished the PMR. Transcriptomics of the MAG indicates that Crz knockout affects the expression of numerous seminal fluid protein genes. Finally, we found that also in female Drosophila melanogaster , disrupted Crz signaling resulted in increased re-mating and reduced oviposition, while CRZ injection suppressed virgin receptivity and increased oviposition. In summary, our study reveals that endogenous female CRZ signaling and male-derived signals cooperate to regulate post-mating transitions in BPHs and Drosophila .