PARENT SESSION
Oral Session 6: Herbivory I: Dynamics, Communities, and Photosynthesis.
Presiding: C Ivey
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room B 114.

Floral damage reduces fecundity in Nemophila menziesii flowers.

McCall, Andrew^*,1, ¹ University of California, Davis, Davis, CA, USA

ABSTRACT- While most of the plant-herbivore literature has focused on damage to leaves, damage to flowers may have severe impacts on plant fitness. Damage to flowers may directly reduce fitness through reductions in ovaries or pollen, or indirectly through petal damage and reduced visitation by pollinators. Very few studies have examined these potentially important indirect effects. In 2003, I conducted a series of experiments to determine the effects of artificial and natural petal damage on seed set, pollen limitation, and pollinator visitation in Nemophila menziesii (Hydrophyllaceae). A two-factor experiment consisting of artificial petal damage and pollen addition showed that damaged flowers were significantly more pollen-limited than control plants, suggesting that pollinators discriminate against damaged flowers. A second experiment where only artificial damage was employed showed that damaged flowers produced significantly less seed than control plants. Finally, I followed the three main pollinators of N. menziesii over two days and showed that they visit proportionally more undamaged flowers than would be expected by chance alone. These data suggest that the indirect effects of floral damage mediated through reduced pollinator attraction may negatively impact individual flower fitness. In addition to these effects, floral damage may play a role in determining the mating system and subsequent progeny quality in self-compatible plants.

Key words: Nemophila menziesii , florivory, pollination, indirect effects