Local and regional determinants of galling-insect richness in Neotropical savanna

Abstract

Abstract:In this study, we determined the effects of plant richness, total plant abundance and abundance of plants with high galling diversity (super-hosts) on the local and regional galling richness in 15 areas of Neotropical savanna in different parts of Brazil. We established in each area 10 plots of 10 × 10 m, where we sampled a total of 131 plant species and 112 galling insect species. We considered all areas at the regional level and plots within each area at the local level. We found that at the regional level a combination of plant richness and plant abundance is the best model to explain the gall-inducing richness. We also found that at the local scale the most important factors are plant abundance and super-host abundance, but the plant richness is irrelevant. These findings confirm recent results that plant richness is an important predictor of galling species richness at the regional level, whereas the vegetation composition and structure act at the local level. Furthermore, this study contributes to the knowledge of the ecology of galling by showing how local factors influence the richness of this insect guild.