Effect of physiological state and prior experience on host selection of pea leaf weevil (Coleoptera: Curculionidae).

Abstract

Herbivores use plant cues to locate food or habitat, with responses to host plants shifting with physiological state to optimize resource use. Prior host experience reduces risk associated with host selection, which is crucial for herbivores with a specialized diet that require specific host plants at certain phenological stages. The pea leaf weevil, Sitona lineatus, is an oligophagous insect herbivore that feeds on leguminous plants. Adults in different physiological states feed on legumes at various times throughout their one-year life cycle. In this study, we investigate how pea leaf weevil physiological state and prior-host experience modulates host finding behavior. We show that pea leaf weevil host preference is state-dependent, with pre-reproductive adults preferring faba bean, the host that maximizes larval survival. Prior feeding experience did not alter host preference in any physiological state. This study suggests that pea leaf weevils show phenotypic plasticity in host preference to maximize fitness benefits, consistent with preference-performance hypothesis. In contrast, non-reproductive weevils prioritize feeding to support overwintering preparation rather than optimizing foraging efficiency, highlighting a state-dependent host choice independent of prior host experience.