Resource limitation and the lethal and sublethal effects of a viral pathogen in the Indian meal moth, Plodia interpunctella

The effects of resource limitation and the lethal and sublethal effects of a granulosis virus on a lepidopteran host, the Indian meal moth, Plodia interpunctella , were examined. The food quality was manipulated by the addition of an inert bulking agent (methyl cellulose) which caused the size, development rate and fecundity of the moths to be reduced. The resource quality had no effect on the mortality due to the virus. In contrast, sublethal effects of the virus on pupal weight were more apparent under conditions of resource limitation. Considerable variation between the sublethal effects after challenge with different doses of the virus was found. The balance between deleterious sublethal effects of the virus and the selection of more robust individuals by the bioassays is proposed as a mechanism to explain this variation. Implications for the dynamics of insect hosts and their pathogens are discussed.