Cucumber beetles negatively impact pollinator visitation to cucurbit flowers

Abstract Herbivorous pests in agricultural systems are often characterised by their direct impact on crops, however indirect effects can compromise critical agroecosystem services like pollination. Cucurbit production relies on pollinators, but also suffers from cucumber beetles ( Acalymma vittatum and Diabrotica spp.) that have an affinity for cucurbit flowers, which may reduce pollination. Over four field seasons, we observed pollination in two cucurbit crops, watermelon ( Citrullus lanatus ) and pumpkin ( Cucurbita pepo ) and assessed the impact of flower‐infesting cucumber beetles on the identity, number, and duration of pollinator visits. In all years of the study and across both crops, pollinator visitation decreased as cucumber beetle density increased. Wild bees disproportionately supplied pollination services to infested flowers and were responsible for the majority (60%–70%) of visitation at higher floral infestations (>5 beetles/flower). Supplemented pollinators spent >50% less time on flowers infested with beetles compared to flowers without beetles, however this was only noted in 1 year in watermelon. While herbivory is known to impact pollination in cucurbits, we demonstrate that the presence of herbivores in cucurbit flowers can also impact pollinator activity. Further, these changes may have important implications to the pollination and pest management programs used in these systems.