Insects harbor numerous endosymbionts, including bacteria, fungi, yeast, and viruses, which could affect the ecology and behavior of their hosts. However, data regarding the effect of environmental factors on endosymbiotic bacteria of Leptocybe invasa (Hymenoptera: Eulophidae) are quite rare. In this study, we assessed the diversity of endosymbiotic bacteria of L. invasa from 10 different geographic populations collected across China through the Illumina MiSeq platform. A total of 547 OTUs were generated, which were annotated into 19 phyla, 33 classes, 75 orders, 137 families, and 274 genera. The dominant bacteria detected in L. invasa were Rickettsia, and Pantoea, Enterobacter, Pseudomonas, Acinetobacter, and Bacillus were also annotated among each population. Nevertheless, the endosymbiotic bacterial abundance and diversity varied among different populations, which was related to the local climate (annual mean high temperature).The bacterial function prediction analysis showed that these endosymbiotic bacteria were concentrated in metabolism, such as carbohydrate, amino acid, and energy metabolism. Overall, the results provide a comprehensive description of the endosymbiotic bacteria in 10 different populations of an important eucalyptus pest L. invasa, and

Leptocybe invasa Fisher et LaSalle is a global invasive pest that seriously damages Eucalyptus plants. Studying the genetic diversity, genetic structure and introgression hybridization of L. invasa in China is of great significance for clarifying the breeding strategy, future invasion and diffusion trends of L. invasa in China and developing scientific prevention and control measures. Genetic diversity and phylogenetic analyses of 320 L. invasa female adults from 14 geographic populations in China were conducted using 10 polymorphic microsatellite loci (SSRs) and mitochondrial DNA cytochrome oxidase I gene sequences (COIs). (1) The Bayesian phylogenetic tree and haplotype network diagram showed that only haplotype Hap3 existed in L. invasa lineage B in China, while haplotypes Hap1 and Hap2 existed in lineage A, among which haplotype Hap2 was found for the first time. The nucleotide and haplotype diversities of lineage A were higher than those of lineage B. (2) The SSR genetic diversity of the Wuzhou Guangxi, Ganzhou Jiangxi and Panzhihua Sichuan populations was higher than that of the other 11 populations, and the SSR genetic diversity of lineage A was higher than that of lineage B. (3) The AMOVA analysis of mitochondrial COI data showed that 75.55% of the variation was among populations, and 99.86% of the variation was between lineages, while the AMOVA analysis of nuclear SSR data showed that 35.26% of the variation was among populations, and 47.04% of the variation was between lineages. There were obvious differences in the sources of variation between the COI and SSR data. (4) The optimal K value of COI and SSR data in structure analysis was 2, and PCoA analysis also divided the dataset into two obvious categories. The UPMGA phylogenetic tree based on SSR data clustered 14 geographic species into two groups. The results of genetic structure analysis supported the existence of two lineages, A and B, in China. (5) Structural analysis showed that there was obvious introgressive hybridization in Wuzhou Guangxi, Ganzhou Jiangxi, Panzhihua Sichuan and other populations. These results suggest that lineage introgressive hybridization has occurred in the L. invasa population in China. The introgressive hybridization degree and genetic diversity of lineage A are obviously higher than those of lineage B. Lineage introgressive hybridization may be the driving force for further L. invasa invasion and diffusion in China in the future.

The white-striped longhorn beetle Batocera horsfieldi (Coleoptera: Cerambycidae) is a polyphagous wood-boring pest that causes substantial damage to the lumber, fruit and nut industry. Here, next-generation sequencing was used to generate a whole genome survey dataset to provide fundamental information of its genome and develop genome-wide microsatellite markers for it. The genome size of B. horsfieldi was estimated as approximate 520 Mb by using K-mer analyses, and its heterozygosity ratio and repeat sequence ratio were 0.26% and 51.03%, respectively. The assembled genome was 528.56Mb with GC content of 35.40%. A total of 121750 microsatellite motifs were identified. The most frequent repeat motif was mononucleotide with a frequency of 85.84%, followed by 8.08% of dinonucleotide, 5.04% of trinonucleotide, 0.73% of tetranonucleotide, 0.20% of pentanonucleotide and 0.12% of hexanonucleotide motifs. The AT/AT, TA/TAand GA/TC repeats were the most abundant motifs of dinucleotide motifs, and AAT/ATT, TAA/TTA and ATA/TAT were the most abundant motifs of trinucleotide motifs, respectively. ninety six pairs of SSR primers were randomly selected for PCR amplification and agarose gel electrophoresis detection, among which 56 pairs of primers can be effectively amplified to obtain the target fragment. In summary, various candidate microsatellite markers were identified and characterized in this study using genome survey analysis.

No abstract