Plants often must defend themselves against antagonisms on several different tissues while still attracting mutualists. Herbivory can reduce plant fitness directly, through resource allocation, or indirectly via interactions with other species such as pollinators. This study investigated the combined effects of leaf herbivory, root herbivory, and pollination on subsequent damage, pollinator preference, and plant performance in a field experiment using butternut squash (Cucurbita moschata). Leaf and root herbivory were applied using adult and larval striped cucumber beetles (Acalymma vittatum), a cucurbit specialist. Leaf herbivory had the greatest impact on plant performance, reducing staminate flower production, fruit number, and seed weight. Leaf herbivory also reduced subsequent pistillate floral damage and powdery mildew (Sphaerotheca fuliginea) infection, suggesting some induced defenses against both herbivores and pathogens. In spite of these induced defenses, the overall effect of leaf herbivory on plant performance was negative. Root herbivory and pollination had no effect on subsequent damage, pollinator preference, or plant performance, and there were few significant treatment interactions. Neither leaf nor root herbivory reduced pollinator visitation or the expression of floral traits, indicating that reductions in plant performance from herbivory were due to direct rather than indirect effects. In addition, no measured aspect of reproduction was pollen limited. Our study reveals the combined impacts of leaf herbivory, root herbivory, and pollination on plant performance using butternut squash in an agroecosystem.
