The relationship of DNA methylation and sex-biased gene expression is of high interest, it allows research into mechanisms of sexual dimorphism and the development of potential novel strategies for insect pest control. The Asian citrus psyllid, Diaphorina citri (Kuwayama), is a major vector for the causative agents of Huanglongbing (HLB), which presents an unparalleled challenge to citrus production worldwide. Here, we identify the X chromosome of D. citri and investigate differences in the transcription and DNA methylation landscapes between adult virgin males and females. We find a large number of male-biased genes on the autosomes and a depletion of such on the X chromosome. We have also characterised the methylome of D. citri, finding low genome-wide levels, which is unusual for an hemipteran species, as well as evidence for both promoter and TE methylation. Overall, DNA methylation profiles are similar between the sexes but with a small number of differentially methylated genes found to be involved in sex differentiation. There also appears to be no direct relationship between differential DNA methylation and differential gene expression. Our findings lay the groundwork for the development of novel epigenetic-based pest control methods, and given the similarity of the D. citri methylome to other insect species, these methods could be applicable across agricultural insect pests.

The relationship of DNA methylation and sex-biased gene expression is of high interest, it allows research into mechanisms of sexual dimorphism and the development of potential novel strategies for insect pest control. The Asian citrus psyllid, Diaphorina citri Kuwayama, is a major vector for the causative agents of Huanglongbing (HLB), which presents an unparalleled challenge to citrus production worldwide. Here, we identify the X chromosome of D. citri and investigate differences in the transcription and DNA methylation landscapes between adult virgin males and females. We find a large number of male-biased genes on the autosomes and a depletion of such on the X chromosome. We have also characterised the methylome of D. citri, finding low genome-wide levels, which is unusual for an hemipteran species, as well as evidence for both promoter and TE methylation. Overall, DNA methylation profiles are similar between the sexes but with a small number of differentially methylated genes found to be involved in sex differentiation. There also appears to be no direct relationship between differential DNA methylation and differential gene expression. Our findings lay the groundwork for the development of novel epigenetic-based pest control methods, and given the similarity of theD. citri methylome to some other insect species, these methods could be applicable across agricultural insect pests.

Five new species of the genus Meta C.L. Koch, 1836 from the Gongligong Mountains, Yunnan are described: Meta hamata sp. nov. (♂♀), M. longlingensis sp. nov. (♂), M. tangi sp. nov. (♂♀), M. yani sp. nov. (♂♀) and M. yinae sp. nov. (♂♀). Detailed descriptions of somatic features and genitalic characters, photos of the body and genital organs, line drawings of the copulatory organs and distribution maps are provided.

A new Linyphiinae genus Zhezhoulinyphiagen. nov. from Yunnan Province is described together with its two new species: Z.caperatasp. nov. (♂) and Z.denticulatasp. nov. (♂, ♀). Centromerusyadongensis Hu & Li, 1987 is transferred to Zhezhoulinyphiagen. nov. and a new combination, Z.yadongensis (Hu & Li, 1987), comb. nov. is proposed.

Four new species of the genus Cicurina are described: C. daweishanensis spec. nov. (female), C. kekei spec. nov. (male and female), C. lichuanensis spec. nov. (male and female) and C. yuelushanensis spec. nov. (male and female). Photos of body and copulatory organs, line drawings of copulatory organs, as well as the locality map are provided. The type specimens of Cicurina eburnata Wang, 1994 were reexamined for the comparison of allied species. Photos of C. calyciforma Wang & Xu, 1989 are also presented in order to compare it with two new species.