Wasp florivory decreases reproductive success in an epiphytic bromeliad Alfredo Cascante-Marı ´n Jan H. D. Wolf J. Gerard B. Oostermeijer Received: 13 May 2008 / Accepted: 3 October 2008 Ó Springer Science+Business Media B.V. 2008 Abstract Flower predation or florivory may alter the sexual expression, floral display, and reduce the reproductive success in plants. In this article, we estimated the effect of florivory on the reproductive success of the epiphytic bromeliad Werauhia gladi- oliflora during 2001–2003 in a premontane area in Costa Rica. Floral buds of W. gladioliflora are attacked by the wasp Eurytoma werauhia (Eurytom- idae), which inhibits flower anthesis. Nearly, a quarter of the sampled population flowers were lost due to wasp infection and it accounted for nearly 70% of the reduction in fruit set. Flowers located on the inflorescence upper segment had a higher attack incidence. In the studied population, florivory has a major role in the reproductive success of W. gladi- oliflora. Florivory on epiphytic plants is scarcely reported in the literature, but evidence suggests that this phenomenon is more spread in the epiphytic community. Whether florivory in W. gladioliflora is a selective pressure influencing the reproductive success or a localized factor operating at the studied population is a subject requiring additional data. Keywords Costa Rica  Eurytoma  Eurytomidae  Flower predation  Fruit set Introduction Florivory or damage caused to developing floral buds or mature flowers before the development of the seed coat has direct implications on the plant reproductive success. Floral feeders may damage the reproductive organs (e.g., floral buds, androecium, and gynoecium) altering the sexual expression of plants and the availability of flowers for pollination. Most hypoth- eses explaining the low reproductive success in hermaphroditic plants, i.e., the low mature fruits to flowers ratio, relate that phenomenon to factors associated with pollination, such as pollen limitation, progeny selection, resource limitation, and pollinator attraction (Stephenson 1981). The role of florivory as a selective force affecting the reproductive success and floral trait evolution in plants is little documented and remains largely understood. A few studies have examined the negative effect of florivorous animals on the repro- ductive success of their plant preys. For instance, pollen-feeding flies altered the male expression in the tropical herb Centropogon solanifolius (Campanula- ceae) (Weiss 1996). In Bombacaceae trees, Present Address: A. Cascante-Marı ´n (&) Departamento de Historia Natural, Museo Nacional de Costa Rica, apartado postal, 749-1000 San Jose, Costa Rica e-mail: alfredo.cascante@gmail.com J. H. D. Wolf  J. G. B. Oostermeijer Institute for Biodiversity and Ecosystem Dynamics (IBED), Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands 123 Plant Ecol DOI 10.1007/s11258-008-9522-y