Disarming the paradox of sublethal plant defense against insects: Trirhabda virgata larval development time and leaf tissue loss on Solidago altissima

Although the fitness benefits of traits that kill herbivores are obvious, the contention that sublethal antiperformance traits have evolved as plant defenses has proved more controversial. Traits that slow herbivore development seem particularly paradoxical, given the common assumption that a protracted feeding period will lead to greater total consumption. Whereas this assumption is superficially reasonable, there is very little evolutionarily relevant evidence to suggest that plants on which larval development is slower actually lose more tissue. For the assumption underlying the sublethal‐defense paradox to be valid, plant traits that affect larval development time and tissue loss must be positively correlated genetically within natural plant populations. In this study, we examined the relationship between larval development time of the beetle Trirhabda virgata LeConte (Coleoptera: Chrysomelidae) and plant tissue loss by its host plant Solidago altissima L. (Asteraceae). Plant genets on which the larval development time was longer ended up losing less leaf area than plant genets that allowed quicker larval development. This negative genetic correlation contradicts the common assumption that greater sublethal resistance leads to increased tissue loss. Combined with other hypothesized benefits of sublethal resistance, this result suggests that antiperformance traits may constitute a more potent form of resistance than is generally acknowledged.