Two decades on: A follow-up comparison of beetle (Coleoptera) and spider (Araneae) diversity in a mosaic of farmland, edge, and tropical forest habitats in western Costa Rica
Abstract
The influence of habitat heterogeneity on arthropod diversity and composition in agroecosystems is a central concern in applied entomology. Recently, there has been increased interest in how managed tropical landscapes, such as mixed-used agricultural areas and rainforest fragments, contribute to the conservation of arthropod biodiversity. We present here the results of a field study conducted in the Puriscal region of the Pacific slope of Costa Rica in a rural community characterized by a mixture of secondary forest and farmland. The study, a follow-up to a similar one conducted in the same sites two decades ago, compared beetle and spider diversity among farmland, nearby tropical forest fragments, and edge habitats. Family diversity of Coleoptera and Araneae captured in pitfall traps were compared in each of these habitats, and similarity indices across habitats were calculated for collected specimens. Morphometric analyses were conducted on specimen body sizes. Similar to our previous findings, we found that spider and beetle diversity and species composition varied among the different habitats studied, but with distinctly different taxonomic responses. In particular, beetle diversity varied markedly among the three habitats, with the highest levels of diversity in edge habitats; spider diversity was similar across all three habitats. Beetle species composition was more similar between adjacent habitats (crop-edge or edge-forest) than non-adjacent habitats (crop-forest). Morphometric analyses for both groups revealed that larger body sizes were found across the board in edge habitats, suggesting relatively simply landscapes (such as pasturelands) may facilitate larger individuals with higher mobility capability regardless of taxon.
Robert J. Tournay, John E. Banks, Hannah E. Kim, Eric I. Barajas, Angel Solis "Two decades on: A follow-up comparison of beetle (Coleoptera) and spider (Araneae) diversity in a mosaic of farmland, edge, and tropical forest habitats in western Costa Rica," The Pan-Pacific Entomologist, 102(1), 1-14, (31 March 2026) https://doi.org/10.3956/2026-102.1.1