Cardel Sharp, Yuria , Koptur, Suzanne .
Effects of herbivory on reproductive success - an experimental investigation with a perennial legume, Centrosema virginianum (Fabaceae: Papilionideae).
The effects of mild and severe defoliation were measured in greenhouse-propagated clones of the native butterfly pea, Centrosema virginianum. The direct effects on male and female fitness in this perennial, partially self-compatible, hermaphroditic plant were measured, to determine which reproductive features, if any, were substantially affected by foliar damage. Two levels of foliar herbivory were applied throughout plant growth. Flower size decreased with increasing levels of herbivory, and genotypes responded differently to foliar herbivory damage. Nectar sugar concentration and nectar volume did not differ among treatments. Damaged plants produced less pollen than undamaged plants for both mild and severe herbivory levels. Surprisingly, after severe leaf damage, flowers produced larger pollen grains, suggesting a possible trade-off between pollen size and pollen number. Total seed set decreased concordantly with the level of damage compared with control plants, and fewer seeds were produced by self-pollination than by cross-pollination. Maternal effects were not significant and there was not any detectable interaction with them. We conclude that Centrosema virginianum has a negative female-male component relationship, tolerating mild levels of herbivory with very little (6% reduction) cost for the total fitness components measured, and severe herbivory with only a 17% reduction in overall fitness. The most severe herbivory treatment plants favored the male fitness component over the female fitness component.
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1 - Florida International University, Department of Biological Sciences, Miami, FL, 33199, USA
2 - Florida International University, Deparment of Biological Sciences, 11200 SW 8th St., Miami, Florida, 33199, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Alpine B/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 1:30 PM