Damage byNeochetinaWeevils (Coleoptera: Curculionidae) Induces Resistance inEichhornia crassipes(Commelinales: Pontederiaceae)

Abstract

Induced resistance in invasive plants might influence herbivore performance or preference, and hamper herbivore-based biological control management. Specialist weevils Neochetina eichhorniae Hustache (Coleoptera: Curculionidae) and N. bruchi Warner (Coleoptera: Curculionidae) are two herbivores commonly used to control Eichhornia crassipes (Mart.) Solms (Commelinales: Pontederiaceae), a destructive and widespread invasive plant. However, we do not know whether Neochetina weevils induce resistance in E. crassipes. I report results from excised-leaf bioassay and whole-plant choice experiments testing adult weevil preference and performance in response to previous damage. I found that adult weevil damage induced resistance in E. crassipes, decreasing weevil performance, but simulated damage did not influence weevil performance in a comparable way. Simulated damage did, however, influence weevil preference. This study is the first test for induced resistance to Neochetina weevil herbivory in Eichhornia crassipes.