Influence of leaf and root herbivory by the striped cucumber beetle (Acalymma vittatum) on pollination and plant performance in butternut squash
Kristen R. Hladun, firstname.lastname@example.org, University of Massachusetts - Amherst, Department of Plant, Soil and Insect Sciences and Graduate Program in Plant Biology, 102 G Fernald Hall, 270 Stockbridge Rd, Amherst, MA and Lynn S. Adler, University of Massachusetts - Amherst, Department of Plant, Soil and Insect Sciences and Graduate Program in Organismic and Evolutionary Biology, 209 E Fernald Hall, 270 Stockbridge Rd, Amherst, MA.
The combined effects of leaf and root herbivory by the striped cucumber beetle (Acalymma vittatum F.) on subsequent damage, pollinator preference, and plant performance were investigated using butternut squash (Cucurbita moschata Duch. ex Poir). Experiments were conducted in the field from June through October 2005. Leaf and root herbivory were applied using adult and larval striped cucumber beetles, 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 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 by squash bees (Peponapis pruinosa Say) or honey bees (Apis mellifera L.). Herbivory also did not affect 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.
Species 1: Coleoptera Chrysomelidae Acalymmavittatum (striped cucumber beetle) Species 2: Violales Cucurbitaceae Cucurbitamoschata (butternut squash) Species 3: Hymenoptera Anthophoridae Peponapispruinosa (squash bee)