Trade-Offs with Resistance to a Granulosis Virus in the Indian Meal Moth, Examined by a Laboratory Evolution Experiment

Abstract

When microbial agents are used as pest-control agents, resistance in the host may be selected for. If resistance occurs there are potentially fitness costs due to trade-offs between resistance and other life-history traits. Genotypic trade-offs with resistance to a virus in a lepidopteran host are examined by a micro-evolutionary selection experiment. Six populations of the Indian meal moth, Plodia interpunctella, were established, three of which supported a granulosis virus infection (selected insects) while the remaining three acted as virus-free controls. After a period of 2 years, bioassays with the virus showed that selected moths were 1.96-fold more resistant to infection (LD 50 s) than those derived from the virus-free control populations