Influence of leaf herbivory, root herbivory, and pollination on plant performance in Cucurbita moschata

Abstract

Abstract 1. Plants experience herbivory on many different tissues that can affect reproduction directly by damaging tissues and decreasing resource availability, or indirectly via interactions with other species such as pollinators.2. 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 manipulated using adult and larval striped cucumber beetles (Acalymma vittatum F.), a cucurbit specialist.3. Leaf herbivory reduced subsequent pistillate floral damage and powdery mildew (Sphaerotheca fuliginea) infection. In spite of these induced defences, the overall effect of leaf herbivory on plant reproduction was negative. Leaf herbivory reduced staminate flower production, fruit number, and seed weight. In contrast, root herbivory had a minimal impact on plant reproduction.4. Neither leaf nor root herbivory altered pollinator visitation or floral traits, suggesting that reductions in plant performance from herbivory were as a result of direct rather than indirect effects. In addition, no measured aspect of reproduction was pollen limited.5. Our study reveals that although leaf herbivory by the striped cucumber beetle can protect against subsequent damage, this protection was not enough to prevent the negative impacts on plant performance.