Leaf Damage Decreases Pollen Production and Hinders Pollen Performance in Cucurbita Texana

Abstract

Leaf damage is known to adversely affect reproductive output through the female (fruit and seed) function, but little is known about the effects of leaf damage on the male function of plants. This study simulates the timing, location, and pattern of natural herbivory by diabroticite beetles and shows that leaf damage reduces male reproductive success in Cucurbita texana. Partially defoliated branches of C. texana produced significantly fewer staminate flowers and fewer pollen grains per flower than undamaged branches on the same plant. Moreover, pollen from staminate flowers on partially defoliated plants was less likely to sire seeds than pollen from undamaged plants when deposited onto a stigma with pollen from a tester line, indicating that leaf damage not only decreases pollen production but also adversely affects pollen performance.