Distinct Gut Microbial Enterotypes and Functional Dynamics in Wild Striped Field Mice (Apodemus agrarius) across Diverse Populations

Rodents, including the striped field mouse (Apodemus agrarius), play vital roles in ecosystem functioning, with their gut microbiota contributing significantly to various ecological processes. Here, we investigated the structure and function of 94 wild A. agrarius individuals from 7 geographic populations (45°57' N, 126°48' E; 45°87' N, 126°37' E; 45°50' N, 125°31' E; 45°59' N, 124°37' E; 46°01' N, 124°88' E; 46°01' N, 124°88' E; 46°01' N, 124°88' E), revealing two distinct enterotypes (Type1 and Type2) for the first time. Each enterotype showed unique microbial diversity, functions, and assembly processes. Firmicutes and Bacteroidetes dominated, with a significant presence of Lactobacillus and Muribaculaceae. Functional analysis highlighted metabolic differences, with Type1 emphasizing nutrient processing and Type2 showing higher energy production capacity. The analysis of the neutral model and the null model revealed a mix of stochastic (drift and homogenizing dispersal) and deterministic processes (homogenous selection) that shape the assembly of the microbiota, with subtle differences in the assembly processes between the two enterotypes. Correlation analysis showed that elevation and BMI were associated with the phylogenetic turnover of microbial communities, suggesting that variations in these factors may influence the composition and diversity of the gut microbiota in A. agrarius. Our study sheds light on gut microbial dynamics in wild A. agrarius populations, highlighting the importance of considering ecological and physiological factors in understanding host-microbiota interactions.

Genetic Diversity and DNA Barcoding of Thrips in Bangladesh

Thrips are economically important pests, and some species transmit plant viruses that are widely distributed and can damage vegetables and cash crops. Although few studies on thrips species have been conducted in Bangladesh, the variation and genetic diversity of thrips species remain unknown. In this study, we collected thrips samples from 16 geographical locations throughout the country and determined the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) gene in 207 thrips individuals. Phylogenetic analysis revealed ten genera (Thrips, Haplothrips, Megalothrips, Scirtothrips, Frankliniella, Dendrothripoides, Astrothrips, Microcephalothrips, Ayyaria, and Bathrips) and 19 species of thrips to inhabit Bangladesh. Among these, ten species had not been previously reported in Bangladesh. Intraspecific genetic variation was diverse for each species. Notably, Thrips palmi was the most genetically diverse species, containing 14 haplotypes. The Mantel test revealed no correlation between genetic and geographical distances. This study revealed that thrips species are expanding their host ranges and geographical distributions, which provides valuable insights into monitoring the diversity of and control strategies for these pests.

Population Genetic Diversity and Structure of Thrips tabaci (Thysanoptera: Thripidae) on Allium Hosts in China, Inferred From Mitochondrial COI Gene Sequences

Thrips tabaci Lindeman is a widely distributed agricultural pest China, which causes damage to many vegetables and cash crops. However, the population genetic variation of this pest in China remains unknown. In this study, the genetic diversity and structure of T. tabaci on Allium hosts collected from 12 geographic locations were evaluated based on mitochondrial cytochrome oxidase subunit I (COI) sequences. Six haplotypes were identified in 247 T. tabaci individuals from 12 geographic locations. All the identified T. tabaci haplotypes were thelytokous populations. The strongest genetic differentiation and relatively low gene flow were found between QHXN and other locations, which might be due to geographic barriers, such as high altitude Qinghai-Tibet Plateau. The lowest genetic variation was found in eastern and southern regions, with only one haplotype identified. The Mantel test showed no correlation between genetic distance and geographical distances. High gene flow between locations with substantial geographical distances suggested that migration of T. tabaci across China might be facilitated through human activities. The results of demographic analysis suggested that T. tabaci in China have undergone a recent demographic expansion. The possible influences of T. tabaci invasion history and human activities on the current haplotype geographical distribution were interpreted and the implications of these findings for T. tabaci management were discussed.

Genetic Divergence of Two Sitobion avenae Biotypes on Barley and Wheat in China

Host plant affinity and geographic distance can play critical roles in the genetic divergence of insect herbivores and evolution of insect biotypes, but their relative importance in the divergence of insect populations is still poorly understood. We used microsatellite markers to test the effects of host plant species and geographic distance on divergence of two biotypes of the English grain aphid, Sitobion avenae (Fabricius). We found that clones of S. avenae from western provinces (i.e., Xinjiang, Gansu, Qinghai and Shaanxi) had significantly higher genetic diversity than those from eastern provinces (i.e., Anhui, Henan, Hubei, Zhejiang and Jiangsu), suggesting their differentiation between both areas. Based on genetic diversity and distance estimates, biotype 1 clones of eastern provinces showed high genetic divergence from those of western provinces in many cases. Western clones of S. avenae also showed higher genetic divergence among themselves than eastern clones. The Mantel test identified a significant isolation-by-distance (IBD) effect among different geographic populations of S. avenae, providing additional evidence for a critical role of geography in the genetic structure of both S. avenae biotypes. Genetic differentiation (i.e., F_ST) between the two biotypes was low in all provinces except Shaanxi. Surprisingly, in our analyses of molecular variance, non-significant genetic differentiation between both biotypes or between barley and wheat clones of S. avenae was identified, showing little contribution of host-plant associated differentiation to the divergence of both biotypes in this aphid. Thus, it is highly likely that the divergence of the two S. avenae biotypes involved more geographic isolation and selection of some form than host plant affinity. Our study can provide insights into understanding of genetic structure of insect populations and the divergence of insect biotypes.

Genetic Variability of the Invasive Species Metcalfa pruinosa (Hemiptera: Flatidae) in the Republic of Korea

Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) has caused substantial agricultural damage since its recent introduction to the Republic of Korea; however, the source of this introduction is still unclear. To examine the genetic divergence and phylogenetic relationships among several populations of M. pruinosa from Korea and foreign countries, 251 COI sequences from 251 samples collected from Korea, France, Italy, Spain, Slovenia, and the United States were newly analyzed, together with seven published COI sequences from Canada. In total, 19 haplotypes were detected from the 258 COI sequences, and three haplotypes, H1, H3, and H9, were detected from samples in Korea. The MJ network and Bayesian inference revealed that the three haplotypes of Korea were closely connected with samples of Italy, Spain, Slovenia, France, and the United States. Our study revealed the possibility of multiple invasions of M. pruinosa from Europe and/or North America into Korea.

Genetic differentiation and diversity of Callosobruchus chinensis collections from China

Callosobruchus chinensis (Linnaeus) is one of the most destructive pests of leguminous seeds. Genetic differentiation and diversity analysis of 345 C. chinensis individuals from 23 geographic populations using 20 polymorphic simple sequence repeats revealed a total of 149 alleles with an average of 7.45 alleles per locus. The average Shannon's information index was 1.015. The gene flow and genetic differentiation rate values at the 20 loci ranged from 0.201 to 1.841 and 11.0-47.2%, with averages of 0.849 and 24.4%, respectively. In the 23 geographic populations, the effective number of alleles and observed heterozygosity ranged from 1.441 to 2.218 and 0.191-0.410, respectively. Shannon's information index ranged from 0.357 to 0.949, with the highest value in Hohhot and the lowest in Rudong. In all comparisons, the fixation index (F ST ) values ranged from 0.049 to 0.441 with a total F ST value of 0.254 among the 23 C. chinensis populations, indicating a moderate level of genetic differentiation and gene flow among these populations. Analysis of molecular variance revealed that the genetic variation within populations accounted for 76.7% of the total genetic variation. The genetic similarity values between populations varied from 0.617 to 0.969, whereas genetic distances varied from 0.032 to 0.483. Using unweighted pair-group method using arithmetical averages cluster analysis, the 23 geographic collections were classified into four distinct genetic groups but most of them were clustered into a single group. The pattern of the three concentrated groups from polymerase chain reactions analysis showed a somewhat different result with cluster.

Homology difference analysis of invasive mealybug species Phenacoccus solenopsis Tinsley in Southern China with COI gene sequence variability

The mealybug species Phenacoccus solenopsis (P. solenopsis) has caused much agricultural damage since its recent invasion in China. However, the source of this invasion remains unclear. This study uses molecular methods to clarify the relationships among different population of P. solenopsis from China, USA, Pakistan, India, and Vietnam to determine the geographic origin of the introduction of this species into China. P. solenopsis samples were collected from 25 different locations in three provinces of Southern China. Samples from the USA, Pakistan, and Vietnam were also obtained. Parts of the mitochondrial genes for cytochrome oxidase I (COI) were sequenced for each sample. Homologous DNA sequences of the samples from the USA and India were downloaded from Gen Bank. Two haplotypes were found in China. The first was from most samples from the Guangdong, Guangxi, and Hainan populations in the China and Pakistan groups, and the second from a few samples from the Guangdong, Guangxi, Hainan populations in the China, Pakistan, India, and Vietnam groups. As shown in the maximum likelihood of trees constructed using the COI sequences, these samples belonged to two clades. Phylogenetic analysis suggested that most P. solenopsis mealybugs in Southern China are probably closely related to populations in Pakistan. The variation, relationship, expansion, and probable geographic origin of P. solenopsis mealybugs in Southern China are also discussed.

Resistance of Trisomic and Diploid Hybrids of Beta vulgaris and B. procumbens to the Sugarbeet Nematode, Heterodera schachtiis Arnold

Trisomic and diploid hybrids of sugarbeet (Beta vulgaris L.) X wild beet (B. procumbens Chr. Sin.) inherited the gene for resistance to Heterodera schachtii Schm. from B. procumbens. The hybrids showed partial resistance to H. schachtii, manifested in failure of larvae to reach maturity. Although significantly greater numbers of female nematodes developed on plants inoculated with populations from the Netherlands or Italy than on plants inoculated with a population from the Salinas Valley, California. the totals for all populations on resistant plants were small. Greater numbers of males than females developed on root-slice cultures of resistant hyhrids when compared to a susceptible cultivar.