已知有十二种植食性昆虫具有不同的生物型,其中七种属于蚜科Aphididae麦二叉蚜Schizaphis graminum(Rondani),是美国大平原中麦类作物和高梁的一种主要害虫.在美国,麦二叉蚜生物型的产生,在一定程度上是由于这种害虫繁殖迅速和孤雌生殖引起的.此外,作物获得对麦二叉蚜的抗性是由单基因起的作用.麦二叉蚜至少为害七十八种禾本科植物;然而Gibson和Plumb(1977)报道,广食性害虫种类出现生物型的频率远低于单食性或寡食性种类. Twelve herbivorous insects are known to have different biotypes, seven of which belong to the Aphididae family Schizaphis graminum (Rondani), a major pest of the wheat crops and sorghum in the Great Plains. In the United States, The generation of the biotype of wheat aphid is partly due to the rapid propagation of such pests and parthenogenesis.In addition, the resistance of crops to the wheat aphid is mediated by a single gene. Aphis depict at least seventy-eight species of gramineous plants; however, Gibson and Plumb (1977) reported that the prevalence of polyphagous pest species is much less frequent than that of the simplex or the non-herbivorous species.