Saproxylic fly diversity in a Costa Rican forest mosaic

Abstract

ABSTRACT Dead wood is a microcosm of biological diversity. Saproxylic insect diversity at the global level is immense, with estimates that up to one third of forest dwelling species rely on moribund or dead wood at some point in their life cycle. Most studies on saproxylic insects have focused on taxa such as beetles, or on areas like the northern temperate regions. This paper presents the first assessment of the diversity of tropical saproxylic Diptera, from the Osa Peninsula of Costa Rica. Forty-one trees representing nine species and six plant families were sampled in a rearing experiment designed to study saproxylic beetles. In total, 272 individuals attributable to 18 families of Diptera were reared as bycatch. Low abundance and species richness of flies was observed overall. A majority of taxa were in saprophagous and mycophagous larval feeding guilds, followed by predators. Host associations, successional stage, and stratum preferences are estimated for the more abundant species. The results support previous findings regarding saproxylic Diptera and their association with moist wood and secondary forests. Interesting trends and noteworthy reared taxa are discussed.