摘要: Numerous physiological processes in insects are tightly regulated by neuropeptides and their receptors. Although they form an ancient signaling system, there is still a great deal of variety in neuropeptides and their receptors among different species within the same order. Neuropeptides and their receptors have been documented in many hemipteran insects, but the differences among them have been poorly characterized. Commercial grapevines worldwide are plagued by the bug Daktulosphaira vitifoliae (Hemiptera: Sternorrhyncha). Here, 33 neuropeptide precursors and 48 putative neuropeptide G protein-coupled receptor (GPCR) genes were identified in D. vitifoliae. Their expression profiles at the probe and feeding stages reflected potential regulatory roles in probe behavior. By comparison, we found that the Releasing Hormone-Related Peptides (GnRHs) system of Sternorrhyncha was differentiated from those of the other 2 suborders in Hemiptera. Independent secondary losses of the adipokinetic hormone/corazonin-related peptide receptor (ACP) and corazonin (CRZ) occurred during the evolution of Sternorrhyncha. Additionally, we discovered that the neuropeptide signaling systems of Sternorrhyncha were very different from those of Heteroptera and Auchenorrhyncha, which was consistent with Sternorrhyncha's phylogenetic position at the base of the order. This research provides more knowledge on neuropeptide systems and sets the groundwork for the creation of novel D. vitifoliae management strategies that specifically target these signaling pathways.

摘要: Odorant-binding proteins (OBPs) play key roles in the perception of semiochemicals in insects. Several OBPs in insect olfactory systems have been functionally characterized, and they provide excellent targets for pest control. The functions of some OBPs that are highly expressed in the nonsensory organs of insects remain unclear. Here, the physiological function of an OBP (OBP27) that was highly expressed in the nonsensory organs of Spodoptera frugiperda was studied. OBP27 was nested within the Plus-C cluster according to phylogenetic analysis. The transcription of OBP27 steadily increased throughout the development of S. frugiperda, and transcripts of this gene were abundant in the fat body and male reproductive organs. An OBP27 knockout strain with an early frameshift mutation was obtained using the clustered regularly interspaced palindromic repeats (CRISPR) / CRISPR-associated protein 9 (Cas9) system. The development time of OBP27(-/-) larvae was significantly longer than that of other larvae. Both male and female OBP27(-/-) pupae weighed significantly less than wild-type (WT) pupae. In crosses of OBP27(-/-) males or females, the mating rate was lower and the mating duration was longer for OBP27(-/-) male-WT female pairs than for WT-WT pairs. By contrast, the mating rate, hatching rate, and number of eggs of OBP27(-/-) female-WT male pairs and WT-WT pairs were similar. These findings indicate that OBP27 plays an important role in the larval development and mating process in male adults. Generally, our findings provide new insights into the physiological roles of nonsensory OBPs.

摘要: Multiple mating by both sexes is common among sexually reproducing animals. Small hive beetles (SHB), Aethina tumida, are parasites of bee nests endemic to sub-Saharan Africa and have become a widespread invasive species. Despite the considerable economic damages they can cause, their basic biology remains poorly understood. Here we show that male and female small hive beetles can mate multiple times, suggesting that costs for mating are low in this species. In an invasive A. tumida population in the United States, a combination of laboratory experiments for males and paternity analysis with eight polymorphic DNA microsatellite markers for field-caught females were used to estimate the number of mating by both sexes. The data show that females and males can mate multiple times-females mated with up to eight males, whereas males mated with at least seven females. The results also showed that A. tumida displayed a skewed paternity, although this was not consistent among the tested females. Thus, first or last male advantage seem to be unlikely in A. tumida. Our observations that individuals of both sexes of A. tumida can mate multiple times opens new research avenues for examining drivers of multiple mating and determining the role it may play in promoting biological invasions.

摘要: DNA methylation and transcription factors play roles in gene expression and animal development. In insects, DNA methylation modifies gene bodies, but how DNA methylation and transcription factors regulate gene expression is unclear. In this study, we investigated the mechanism that regulates the expression of Bombyx mori Zinc finger protein 615 (ZnF 615), which is a downstream gene of DNA methyltransferase 1 (Dnmt1), and its effects on the regulation of embryonic development. By progressively truncating the ZnF 615 promoter, it was found that the -223 and -190 nt region, which contains homeobox (Hox) protein cis-regulatory elements (CREs), had the greatest impact on the transcription of ZnF 615. RNA interference (RNAi)-mediated knockdown and overexpression of Hox family genes showed that Hox A1-like can enhance the messenger RNA level of ZnF 615. Further studies showed that Hox A1-like regulates ZnF 615 expression by directly binding to the -223 and -190 nt region of its promoter. Simultaneous RNAi-mediated knockdown or overexpression of Hox A1-like and Dnmt1 significantly inhibited or enhanced the regulatory effect of either gene alone on ZnF 615 expression, suggesting that both DNA methylation of gene bodies and binding of transcription factors to promoters are essential for gene expression. RNAi-mediated knockdown of Hox A1-like and Dnmt1 showed that the embryonic development was retarded and the hatching rate was decreased. Taken together, these data suggest that Hox A1-like and DNA methylation enhance the expression of ZnF 615, thereby affecting the development of B. mori embryos.

摘要: Fatty acyl reductases (FARs) are key enzymes that participate in sex pheromone biosynthesis by reducing fatty acids to fatty alcohols. Lepidoptera typically harbor numerous FAR gene family members. Although FAR genes are involved in the biosynthesis of sex pheromones in moths, the key FAR gene of Spodoptera litura remains unclear. In this work, we predicted 30 FAR genes from the S. litura genome and identified a domain duplication within gene SlitFAR3, which exhibited high and preferential expression in the sexually mature female pheromone glands (PGs) and a rhythmic expression pattern during the scotophase of sex pheromone production. The molecular docking of SlitFAR3, as predicted using a 3D model, revealed a co-factor NADPH binding cavity and 2 substrate binding cavities. Functional expression in yeast cells combined with comprehensive gas chromatography indicated that the SlitFAR3 gene could produce fatty alcohol products. This study is the first to focus on the special phenomenon of FAR domain duplication, which will advance our understanding of biosynthesis-related genes from the perspective of evolutionary biology.