Changing interactions among persistent species as the major driver of seasonal turnover in plant-caterpillar interactions.

Abstract

β diversity of herbivorous insects in the tropics is usually very high, and there is often strong dissimilarity in herbivore species composition across different spatial scales and different abiotic gradients. Similarly, turnover is high for trophic interactions between herbivorous insects and their host plants. Two factors have been proposed to explain temporal or spatial differences in trophic interactions: changes in species composition and temporal changes in the behavior of shared species. The goal of this study was to evaluate determinants of high β diversity of trophic interactions between lepidopteran caterpillars and their host plants across dry and rainy seasons and their transitions. Over the course of a year, interaction diversity data were collected from 275 temporary plots in Cerrado vegetation, comprising 257 species of caterpillars, 137 species of host plants and 503 different trophic interactions. All these diversity parameters varied across seasons. Species assemblages of caterpillars and plants were different among the four seasons, and there was a high turnover of interactions between the seasons. The high temporal β diversity of trophic interactions was mostly due to interaction rewiring between co-occurring species, as opposed to changes in species composition over time.