Effects of Maize Mosaic Virus on the Life History and Morphology of Peregrinus Maidis (Hemiptera: Delphacidae)

Maize mosaic virus (MMV; Rhabdoviridae) is transmitted in a persistent-propagative manner by the corn planthopper, Peregrinus maidis. We examined the fitness of P. maidis developing on healthy or MMV-infected corn leaves from either young (< 30 days old) or old (> 55 days old) corn plants. Results showed planthoppers feeding on healthy leaves development significantly faster than planthoppers on MMV-infected leaves. Development on younger leaves was significantly faster compared to older leaves. Since MMV is acquired at a low efficient rate, we segregated insects into 2 categories as determined by ELISA tests: Infected planthoppers, (MMV positive) Exposed planthoppers (MMV negative). The fecundity and longevity of those planthoppers were compared with planthoppers that developed from healthy leaves. Results showed mean longevity was not significantly different between healthy, MMV-exposed, and MMV-infected planthoppers. However, healthy planthoppers were significantly more fecund then both MMV-exposed and MMV infected planthoppers, which displayed similar fecundity. Since the abundance of wing forms may vary in response to host-plant physiology, we examined the effect of MMV on the proportion macropters and brachypters. The proportion of brachypters produced on young healthy and MMV-infected leaves were similar. Conversely, a significantly higher proportion of macropters were produced on older MMV-infected leaves compared to healthy leaves of similar age. Our findings suggest MMV infection may influence the dispersal of P. maidis indirectly through host-plant infection. At early plant infection, MMV supports the production brachypters, however, at later stage of plant infection the virus may promote vector dispersal by triggering larger production of macropters.