Testing for reciprocal trait influence in plant-frugivore interactions using generalized joint attribute modeling

Abstract

ABSTRACTUnder an adaptive hypothesis, the reciprocal influence between mutualistic plants and frugivores is expected to result in dispersal syndromes comprising both frugivore and plant traits that structure fruit consumption. Tests of this adaptive hypothesis, however, focus on traits of either fruits or frugivores but not both and often ignore within-species variation. To overcome these limitations, we analyze traits for the mutualistic ecological network comprisingCarolliabats that feed on and dispersePiperseeds. For these analyses, we use generalized joint attribute modeling (GJAM), a Bayesian modeling approach that simultaneously accounts for multiple sources of variance across trait types. In support of the adaptive hypothesis and indicating niche partitioning amongCarolliabats, we find differential consumption of a suite ofPiperspecies influenced by bat traits such as body size; however,Pipermorphological traits had no effect on bat consumption. Slow evolutionary rates, dispersal by other vertebrates, and unexamined fruit traits, such asPiperchemical bouquets, may explain the lack of association between batPiperconsumption and fruit morphological traits. We have identified a potential asymmetric influence of frugivore traits on plant-frugivore interactions, providing a template for future trait analyses of plant-animal networks.