Early simulated leaf herbivory reduces male reproductive investment a field pumpkin variety of Cucurbita pepo subsp. pepo

            Insect leaf herbivory during early vegetative plant growth can induce later energetic investment in reproductive structures. Reductions in reproductive investment can alter the availability and quality of floral resources offered to insect pollinators, however which floral traits change in response to herbivory vary distinctly among plant families and even between closely related species. Here we investigated the effect of herbivory on the floral resources in the common pumpkin Cucurbita pepo subsp. pepo grown under hoop-house conditions. We applied a simulated herbivory treatment, removing 15% or 50% of leaf biomass over 10 days of early plant growth and measured floral traits over the entire 9-week bloom period. Our results showed that early herbivory stress delayed initial anthesis of male blooms and significantly reduced the number of daily male blooms produced for the first 35 days and cumulatively throughout the entire bloom window. However, the amount of nectar and pollen produced per male bloom did not vary by herbivory treatments, nor did female bloom production. These findings indicate that herbivory can indirectly negatively impact foraging pollinators by reducing bloom number. For specialist pollinators, such as the hoary squash bee, Eucera (Peponapis) pruinosa, who require Cucurbita sp. pollen, such reductions in bloom production could increase the foraging range required to provision nests or reduce reproductive capacity. This study highlights how studying plants over entire phenological cycles can enhance understanding of indirect insect interactions through shared host plant use.