Microsatellites reveal a strong subdivision of genetic structure in Chinese populations of the mite Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

BackgroundTwo colour forms of the two-spotted spider mite (Tetranychus urticae Koch) coexist in China: a red (carmine) form, which is considered to be native and a green form which is considered to be invasive. The population genetic diversity and population genetic structure of this organism were unclear in China, and there is a controversy over whether they constitute distinct species. To address these issues, we genotyped a total of 1,055 individuals from 18 red populations and 7 green populations in China using eight microsatellite loci.ResultsWe identified 109 alleles. We found a highly significant genetic differentiation among the 25 populations (global FST = 0.506, global FST {ENA} = 0.473) and a low genetic diversity in each population. In addition, genetic diversity of the red form mites was found to be higher than the green form. Pearson correlations between statistics of variation (AR and HE) and geographic coordinates (latitude and longitude) showed that the genetic diversity of the red form was correlated with latitude. Using Bayesian clustering, we divided the Chinese mite populations into five clades which were well congruent with their geographic distributions.ConclusionsSpider mites possess low levels of genetic diversity, limit gene flow between populations and significant and IBD (isolation by distance) effect. These factors in turn contribute to the strong subdivision of genetic structure. In addition, population genetic structure results don't support the separation of the two forms of spider mite into two species. The morphological differences between the two forms of mites may be a result of epigenetic effects.

Structure and genetic variation among populations of Euschistus heros from different geographic regions in Brazil

“…Additionally, the rapid and intensive increase in soybean‐planted area in the last decades may be related to the genetic bottleneck signs observed in great part of the samples analyzed (significant values using the Wilcoxon sign‐rank test). Given that the bottleneck analysis (Wilcoxon sign‐rank test) responds to signs of recent decreases in ϴ (Cornuet & Luikart, ) and that the expansion of soybean‐planted area is still ongoing (Flaskerud, ; IBGE, ), our results suggest the influence of a dissemination pattern to new areas as small groups, that is, it could be the occurrence of the founder effect (Sun et al., ).…”

Closely related octopus species show different spatial genetic structures in response to the Antarctic seascape

“…MICROCHECKER v.2.2.3 (Van Oosterhout, Hutchinson, Wills, & Shipley, ) was used to check data for the presence of null alleles, the frequencies of which were estimated using FREENA (Chapuis & Estoup, ). Where significant frequencies of null alleles were detected, false homozygote frequencies were used to adjust the number of null alleles per sample (Sun, Lian, Navajas, & Hong, ). GENEPOP v.4.1.3 (Raymond & Rousset, ; Rousset, ) and FSTAT v.2.9.3 (Goudet, ) were used to provide descriptive statistics: departures from expected Hardy–Weinberg Equilibrium (HWE) conditions, extent of linkage disequilibrium (LD) between loci, numbers of private alleles, allelic richness ( A R ), observed ( H o ) and expected heterozygosity ( H e ) and the amount of genetic differentiation (Wright's [1951] F ST ) among pairs of large (n > 10) samples.…”

Adaptation of acaricide stress facilitates Tetranychus urticae expanding against Tetranychus cinnabarinus in China

“…In China, the two forms coexist, where the red form T. cinnabarinus is distributed throughout China and is considered to be native, while the green form T. urticae , which was first reported in 1983 in Beijing, is considered to be invasive (Dong, Guo, & Niu, 1987; Sun, Lian, Navajas, & Hong, 2012). Tetranychus urticae has recently expanded its distribution from its putative area of introduction in Beijing to many parts of the country, including Hebei, Liaoning, Jilin, Gansu, Anhui, and Yunnan provinces and elsewhere (Meng, Wang, Jiang, & Yi, 2001; Sun et al., 2012).…”

“…Tetranychus urticae has recently expanded its distribution from its putative area of introduction in Beijing to many parts of the country, including Hebei, Liaoning, Jilin, Gansu, Anhui, and Yunnan provinces and elsewhere (Meng, Wang, Jiang, & Yi, 2001; Sun et al., 2012). Unexpectedly, the invading T. urticae has become the most important mite pest in apple orchards in the north of China (Cai, Cheng, & Sha, 2003).…”