Strata use in a canopy-beetle community of a lowland Neotropical rainforest in southern Venezuela

Abstract

AbstractThe stratification in tropical rainforests is well pronounced. This strongly impacts the distribution of arthropods. As part of a larger beetle survey in the northern part of the Amazonian rainforest, I analyze the characteristics of beetle species shared between the canopy and the understory. Linking the strata use of adult beetles in the complex structure of tropical rainforests with their ecological characteristics may uncover causes of the differences in diversity between vertical layers. Seventy out of a total of 862 beetle species in 45 families sampled on 23 canopy-tree species were collected also in the understory. Beetle families represented with most species in the canopy and ground samples comprise Curculionidae, Chrysomelidae, and Carabidae. In Elateridae and Scarabaeidae, the proportion of shared species between both strata amounted to ≥ 20%. In contrast, the species-rich families (≥ 20 canopy species) Cerambycidae, Mordellidae, and Buprestidae did not comprise species sampled in both strata. Adult feeding requirements and larval substrates are discussed as main reasons for the differences in strata use between these beetle families. In addition, different climatic conditions between the exposed canopy and the more uniform understory might cause a migration of adult beetles between both strata and thus, result in intermixing of beetle species from different strata within the forest.