Clonal Diversity and Genetic Differentiation of Sitobion avenae (Hemiptera: Aphididae) From Wheat and Barley in China

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

“…Genetic diversity and divergence among populations are essential in enabling insect species to respond rapidly to evolutionary challenges, thus having significant impacts on the adaptability of insects under constantly changing environmental conditions [1][2][3]. During the long term evolutionary process, insect species could have experienced genetic differentiation and diversification from combined effects of mutation, selection, gene flow, and genetic drift [4][5][6][7]. In this process, gene flow among populations could have been prevented by some environmental barriers, and local selection could be in turn accelerated, thus promoting changes in genetic structure of populations [6][7][8].…”

“…During the long term evolutionary process, insect species could have experienced genetic differentiation and diversification from combined effects of mutation, selection, gene flow, and genetic drift [4][5][6][7]. In this process, gene flow among populations could have been prevented by some environmental barriers, and local selection could be in turn accelerated, thus promoting changes in genetic structure of populations [6][7][8]. Demographic histories involving events of inbreeding and migration can also affect genetic structure of pest insect populations [9,10].…”

“…Many studies have shown that different geographic populations can show patterns of IBE (isolation by environment) or IBD (isolation by distance) (IBD) [11][12][13]. In addition, host plants are another significant factor influencing genetic structure of insect populations, since host-plant associated differentiation appears to be a common phenomenon for insect populations [7,[14][15][16]. Indeed, various biotypes (usu.…”

“…Different insect biotypes can be distinguished by their characteristic response patterns (i.e., differential life-history traits or fitness) on different plants or different varieties of the same plant [21,22]. In particular, aphid species are prone to evolve different biotypes on variable plants because of their unique characteristics like common occurrence of local adaptation and phenotypic plasticity [23][24][25], induction of significant plant responses with saliva [26][27][28], and harboring various primary and secondary endosymbionts (e.g., Buchnera, Regiella and Hamiltonella) [29][30][31].…”

“…Since the late 1990s, there have been a great number of studies that use DNA markers to examine geographic or host-plant associated differentiation of various aphids [2,[36][37][38][39]. But the relative importance of geography and host plant use on the biotype divergence of aphid populations, as well as genetic relationships among different aphid biotypes, is still not well understood [22,[36][37][38].…”