Host Plant Infection by Soybean Mosaic Virus Reduces the Fitness of Its Vector, Aphis glycines (Hemiptera: Aphididae).

Coevolutionary interactions between pathogens and their insect vectors can dramatically impact the fitness of herbivorous insects and patterns of plant disease transmission. Soybean mosaic virus (SMV) is a common disease in soybean production worldwide. Infected seed is the primary source of inoculum in fields and the virus is secondarily spread among plants by the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in a nonpersistent manner. In this study, we compared the biological fitness of A. glycines colonizing both SMV-infected and uninfected soybean plants. Aphids feeding on SMV-infected soybean seedlings were significantly smaller and lighter than those feeding on uninfected plants across life stages. SMV infection caused delayed development of aphid nymphs on soybean seedlings, but this was more than compensated by a reduction in the pre-reproductive period of apterous adults. The fecundity of A. glycines was reduced when feeding on SMV-infected seedlings, resulting in a lower reproductive rate, a longer generation time, and a slower population doubling time. A smaller proportion of aphid offspring developed into alatae when feeding on SMV-infected soybean seedling, and these took longer to mature than their counterparts on uninfected plants. We infer that SMV infection has significantly negative effects on the biological performance of A. glycines, which may be consistent with the long-term coevolution of SMV, soybean, and A. glycines in the transmission cycle of SMV.