More flowers, more pollinators, less fruit: drought increases insect visitation but reduces yield in cucumber

Climate change intensifies drought frequency, posing risks to pollinators both directly and indirectly through changes in floral resource availability. We tested how water limitation alters pollinator-relevant floral traits, visitation, and plant reproductive outcomes in cucumber (Cucumis sativus) using an outdoor field experiment with conventional and drought-tolerant cucumber cultivars. We manipulated water availability (well-watered vs. water-limited) and quantified floral display, nectar rewards, and pollinator visitation during two sampling periods eight days after treatment onset. Contrary to expectations, water limitation did not reduce floral resource availability for pollinators. Instead, both cultivars produced more flowers under drought, particularly the drought-tolerant variety, resulting in increased floral display and higher pollinator visitation rates. Water stress strongly shifted sex ratios toward male flowers, which provide pollen but less nectar than female flowers. However, when averaged across flower types, total nectar availability was maintained under drought, suggesting that pollinator energetic rewards were not reduced and may even be complemented by increased pollen availability. Despite increased visitation to water-limited plants, fruit quantity and quality declined, indicating physiological limitations on fruit development, such as female flower abortion, rather than insufficient pollination. These findings suggest that cucumber-pollinator interactions are resilient, or even enhanced, under drought from the pollinator perspective, while plants incur reproductive costs. This asymmetry highlights that climate-driven changes in plant traits may differentially affect mutualistic partners, with potential benefits for pollinators occurring alongside declines in crop yield.