PARENT SESSION
Oral Session # 21: Herbivory I: Susceptability and Resistance.
Presiding: D Lincoln
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 200.

Intense disturbance enhances plant susceptibility to herbivory: Natural and experimental evidence.

Spiller, David¹, Agrawal, Anurag², ¹ University of California, Davis, Davis, CA² University of Toronto, Toronto, ON, Canada

ABSTRACT- Following Hurricane Lili, which passed directly over the site of our ongoing study in Great Exuma, Bahamas, herbivory increased on devastated islands exposed to the storm surge but not on protected islands. Observations suggested that foliage sprouting on severely damaged shrubs was more susceptible to herbivores than new foliage on undamaged shrubs. To test this hypothesis we conducted a controlled field experiment: hurricane damage was simulated by pruning shrubs on replicated islands. Seven months after the manipulation herbivory was 68% higher on pruned shrubs than on controls. Leaf size and percent nitrogen were higher and leaf toughness and trichome density were lower on pruned shrubs than on controls. The experimental results indicate that enhanced herbivory on exposed islands following Hurricane Lili was caused, at least in part, by increased susceptibility of the sprouted foliage to herbivorous arthropods. Since sprouting occurs on many woody plants following natural or anthropogenic disturbances, the findings in this study may have broad implications.

Key words: herbivory, disturbance, hurricanes, sprouting