Prof. WANG Zhenying Research Group made a progress in research on genetics of genus Os-trinia species not only found the hybrid individuals in nature for the first time but also illus-trated the introgression between divergent corn borer species in sympatry region. The re-search finding was published online in MOLECULAR ECOLOGY, entitled “Introgression be-tween divergent corn borer species in a region of sympatry: Implications on the evolution an-dadaptation of pest arthropods”

Species are defined as distinct biological units within which random mating and high levels of gene flow maintain the reproductive compatibility among individuals. In contrast, random genetic drift and adaptive mutations between spatially or temporally separated populations can result in the accumulation of divergent traits and provide the foundation for reproductive isolation and subsequent biological speciation. Revision of these early concepts has incorpo-rated the acknowledgement that distinct species are often maintained in spite of introgression and that a continuum of species boundaries likely exists. The fate of introgressed alleles is hy-pothesized to be a function of selective advantage within the derived genomic architecture, wherein locally adaptive genome regions, not the genome as a whole, might impact the de-gree of genetic isolation. Selectively advantageous alleles and neutral alleles are assumed to be more freely exchanged, which is in sharp contrast to alleles contributing to reproductive isolation or impacting locally adaptive traits. In addition to this evolutionary perspective, eco-logical dynamics play an important part in introgression within hybrid zones. When species are of close evolutionary relationship and retain the potential for reproductive exchange, asymmetric introgression is likely to occur from the local resident to the invading species. When intraspecific gene flow is sufficiently high to curb the effects of random genetic drift, introgressed alleles are predicted to have a lower probability of increasing in frequency within populations of the invading species.

The Asian corn borer (ACB), Ostrinia furnacalis, and European corn borer (ECB ) O. nubilalis (Lepidoptera: Crambidae), cause severe damage to cultivated maize in spatially distinct geog-raphies and have evolved divergent hydrocarbons as the basis of sexual communication. Fe-males produce blends of pheromone components of O. furnacalis (E- and Z-11-tetradecenyl acetate; E- and Z-12-14:OAc) and O. nubilalis (E- and Z-11-14:OAc) are different.

The European corn borer is native to Europe, the Mediterranean region of African and Asia, through central regions of Asia. The Asian corn borer has a geographic distribution dis-tinct from ECB across regions that stretch from Japan to Northern Australia and most corn growing regions of China. Yili area in Xinjiang is the only ECB distributed region in China. The ACB was introduced into Yili by accident in late of 1980s by accident. So, Yili is the only sympatric area of the two corn borers where we know. This is a good chance for study evolution and genetics of sibling species Corn borers were collected from corn plants at 11 locations in Xinjiang corn growing area and genotyped using high-throughput SNP and microsatellite markers. Maternal lineages were assessed by direct sequencing of mitochondrial cytochrome c oxidase subunit I and II haplotypes, and a high degree of genotypic diversity was demonstrated between lineages based on SNP genotypes. Furthermore, historical introgression was predicted among SNP genotypes only at sympatric locations in the Yili area, whereas in Xinjiang populations only O. furnacalis haplotypes were detected and no analogous introgressed genotypes were pre-dicted. Our detection of putative hybrids and historical evidence of introgression defines Yili area as a hybrid zone between the species in normal ecological interactions and furthermore, might indicate that adaptive traits could spread even between seemingly divergent species through horizontal transmission. Results of this study indicate there may be a continuum in the degree of reproductive isolation between genus Ostrinia species and that the elegance of distinct and complete speciation based on modifications to the pheromone communication might need to be reconsidered.

More details are available on the link bellow:
http://onlinelibrary.wiley.com/doi/10.1111/mec.14387/full