Abstract/Summary

The life histories of insect herbivores are affected by variation in host plant quality, with poor quality typically being associated with reduced herbivore fecundity, size and longevity. Plant pathogens are ubiquitous in nature and can alter host plant quality as experienced by insect herbivores. We asked how host plant infection by the widespread and economically important fungal pathogen Botrytis cinerea affected the life history traits of two aphid species. We found that the life history traits of the black bean aphid Aphis fabae were negatively affected by being reared on infected host plants, showing reduced fecundity, population growth rate, size, off-plant survival time and development rate. In contrast, we found that pea aphids Acyrthosiphon pisum benetted from being reared on infected plants, and that the degree of benet varied between pea aphid clonal lines. This work suggests that the ecological and economic consequences of plant pathogen infection on the dynamics of aphid pests could be difcult to predict.