Detecting Deep Divergence in Seventeen Populations of Tea Geometrid (Ectropis obliqua Prout) in China by COI mtDNA and Cross-Breeding

Abstract

The tea geometrid (Ectropis obliqua Prout, Lepidoptera: Geometridae) is a dominant chewing insect endemic in most tea-growing areas in China. Recently some E. obliqua populations have been found to be resistant to the nucleopolyhedrovirus (EoNPV), a host-specific virus that has so far been found only in E. obliqua. Although the resistant populations are morphologically indistinguishable from susceptible populations, we conducted a nationwide collection and examined the genetic divergence in the COI region of the mtDNA in E. obliqua. Phylogenetic analyses of mtDNA in 17 populations revealed two divergent clades with genetic distance greater than 3.7% between clades and less than 0.7% within clades. Therefore, we suggest that E. obliqua falls into two distinct groups. Further inheritance analyses using reciprocal single-pair mating showed an abnormal F1 generation with an unbalanced sex ratio and the inability to produce fertile eggs (or any eggs) through F1 self-crossing. These data revealed a potential cryptic species complex with deep divergence and reproductive isolation within E. obliqua. Uneven distribution of the groups suggests a possible geographic effect on the divergence. Future investigations will be conducted to examine whether EoNPV selection or other factors prompted the evolution of resistance.

The complete mitochondrial genomes of two vent squat lobsters, Munidopsis lauensis and M. verrilli: Novel gene arrangements and phylogenetic implications

“…The metazoan mitochondrial genome (mitogenome) is typically a circular double strand DNA molecule, encoding 13 protein‐coding (PCG) genes (seven subunits of the NADH dehydrogenase complex, the cytochrome b subunit of the cytochrome bc1 complex, three subunits of the cytochrome c oxidase, and two subunits of ATP synthase), 22 transfer RNAs (tRNA) genes, two ribosomal RNAs (rRNA, rrnS , and rrnL ) genes, and a control region (CR) including sites for the initiation of transcription and replication (Boore, ). Owing to its small genome size, higher evolutionary rates, limited recombination, and maternal inheritance, (Gissi, Iannelli, & Pesole, ; Simon, Buckley, Frati, Stewart, & Beckenbach, ), mitogenome has been widely used in species identification (Fu, Han, & Xiao, ; Kanmiya et al, ), molecular evolution (Cameron, ; Shao et al, ; Shao, Zhu, Barker, & Herd, ), phylogenetic relationship (Cameron, ; Cameron, Yoshizawa, Mizukoshi, Whiting, & Johnson, ; Chen, Wei, Shao, Dou, & Wang, ; Chen, Wei, Shao, Shi, et al, ), and population genetic (Wei et al, ; Zhang et al, ) studies. Although the gene content is relatively conservative, their rearrangements have been frequently reported, particularly in invertebrates at many taxonomic levels (Cameron, Johnson, & Whiting, ; Hassanin, Léger, & Deutsch, ).…”

The Complete Mitochondrial Genome of Aleurocanthus camelliae: Insights into Gene Arrangement and Genome Organization within the Family Aleyrodidae

“…Over the last decade, the mitochondrial (mt) genome sequences have been frequently used to study species discrimination [1,2], molecule evolution [3,4,5,6], phylogenetic inferences [3,4,7,8] and population genetics [9,10], due to their small genome size, rapid evolutionary rate, low level or absence of sequence recombination and evolutionary conserved gene products [11,12]. With a few exceptions, animal mt genome is typically a circular double strand DNA molecule, with a size of 13–20 kb, consisting of a putative control region (CR) and 37 genes: 13 protein-coding genes (PCG), two ribosomal RNA genes (rRNA), and 22 transfer RNA genes (tRNA) [13,14,15,16,17].…”

Asymmetrical reproductive interference between two sibling species of tea looper: Ectropis grisescens and Ectropis obliqua

“…Ectropis grisescens Warren and Ectropis obliqua (Prout) (Lepidoptera: Geometridate: Ennominae) feed on tea leaves and tender buds. They infest thousands of hectares of tea a year, severely reducing growth, and impacting the tea production in the following year (Zhang & Tan, 2004;Zhang et al, 2014). E. grisescens has been reported from Anhui, Fujian, Henan, Hunan, Hubei, Jiangxi and Zhejiang provinces in China (Jiang et al, 2014).…”

“…Despite their morphological similarities, E. obliqua and E. grisescens are two sibling species in the same genus in China (Jiang et al, 2014;Zhang et al, 2014). Our previous research of tea loopers from 17 tea fields in different parts of China shows that the two species, although being morphologically similar, had clear reproductive isolation and variable mitochondrial cytochrome oxidase I (COI) sequences (Zhang et al, 2014). Recently, by microscopic examination of some morphological traits can separate the two species.…”