Fagua Gonzalez, Jose , Ackerman, James .
Consequences of floral visits by ants and invasive honeybees
to the hummingbird-pollinated, Caribbean cactus Melocactus intortus.
The pink, tubular, nectariferous flowers of Melocactusintortus (Cactaceae) in Puerto Rico are visited by native hummingbirds(Anthracothorax dominicus), but also by invasive honeybees (Apis mellifera) and ants (Solenopsis sp.). We sought to determine if the bees and ants significantly alter the pollination of M. intortus by measuring pollinator effectiveness. Using traditional estimates of effectiveness (visitation rate and seed set), our results show that hummingbirds were the most effective pollinators as expected. Bees and ants were less effective, and their contributions were one-fourth to one-tenth of that observed for hummingbirds. We then modified this measure of effectiveness by adding two components, fitness of progeny and temporal availability of visitors, both of which refine estimates of flower visitor effectiveness. With these new estimations, we found that the effectiveness values of all three animal visitors decreased; however, the role of hummingbirds as the principal pollinator was maintained, whereas the effectiveness values of bees and ants approached zero. By these new measures of overall pollinator effectiveness, the invasive honeybees and ants have little effect on the reproductive success of M. intortus.
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University of Puerto Rico-Río Piedras Herbarium
1 - University Of Puerto Rico, Faculty Of Natural Sciences, PO Box 70377, San Juan, PR, 00936-8377, USA
Presentation Type: Poster:Posters for Topics
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM