Lengthmass relationships for macroinvertebrates in freshwater environments of Patagonia (Argentina)

Abstract

Mass-length equations were obtained for aquatic macroinvertebrates collected in di ferent streams and rivers of Patagonia, Argentina. Thirty six taxa were studied: Plecoptera (10 species), Ephemeroptera (3 species, 3 genera), Trichoptera (4 species, 1 genus), Diptera (6 genera), Coleoptera (1 species, 1 genus) Anisoptera (1 genus), Crustacea (2 species), Oligochaeta (1 genus, 1 family), Gasteropoda (1 species) and Turbellaria (1 genus). Additional relationships were obtained at the order level for Plecoptera, Ephemeroptera, Trichoptera and Diptera. Mass-length relationships were estimated by fitting the model Y = aXb linearized by logarithmic transformation) to data of dry mass vs. body length of preserved specimens. The regressions were highly significant and explained a high proportion of variation of the dependent variable, as expressed by the Coefficient of Determination (R2 = 0.580.98). The equations obtained allow the estimation of biomass of invertebrates in Patagonian running waters from measurements of linear dimensions, facilitating calculations of benthic standing crop and of secondary production.