Experience may outweigh cue similarity in maintaining a persistent host-plant-based evolutionary trap

Abstract

Rapid environmental change can decouple previously reliable cues from important resources, causing specialized recognition systems to result in maladaptive behaviors. For native herbivorous insects, such evolutionary traps are often imposed by attractive invasive plants that prove harmful to their offspring. Despite the costs of ovipositing on a poor-quality host, evolutionary traps are expected to persist when overlapping cue sets (cue similarity) link decreased preference for the novel, unsuitable plant with decreased preference for the historical or native resource. We evaluated the role of cue similarity in the persistence of maladaptive oviposition by a native butterfly on a lethal, invasive mustard. While the novel plant shares glucosinolate cues with at least one of the native hosts and the most abundant cue is a strong oviposition stimulant, we found that this cue was not a major driver of preference for either plant. Nor was preference for the two plants correlated, meaning decreased preference for the invasive mustard would not cause butterflies to miss potential oviposition opportunities on the superior native host. Instead, butterfly preference was modified by previous experience in a way that suggests that frequent encounters with native hosts in the wild may buffer butterflies against this evolutionary trap.