Meeting Abstract

P1.23  Friday, Jan. 4  Linking manipulative experiments to field data to test the dilution effect VENESKY, M.; LIU, X.; SAUER, E.*; ROHR, J.; The University of South Florida; Chinese Academy of Sciences; The University of South Florida; The University of South Florida erinsauer@mail.usf.edu

The dilution effect, the hypothesis that biodiversity reduces disease risk, has received support in some systems. However, few dilution effect studies have examined the effects of diversity on more than a single host species or have linked mechanistic experiments to field patterns to establish both causality and ecological relevance. We tested the dilution effect hypothesis in an amphibian-Batrachochytrium dendrobatidis (Bd) system. We show that tadpoles can filter feed Bd zoospores and that the degree of filter feeding was positively associated with their dilution potential. The obligate filter feeder, G. carolinensis, generally diluted the risk of chytridiomycosis for B. terrestris and H. cinerea tadpoles, whereas B.terrestris, an obligate benthos feeder, generally amplified infections for the other species, and species richness was a significant negative predictor of Bd abundance. Field data, at the scale of the entire United States, a scale to which the dilution effect has never been tested, corroborated these laboratory findings and were predictable based on host characteristics, providing hope that there are traits of hosts that can predict their diluting and amplifying capabilities.