Dry mass estimation of tropical aquatic insects using different short-term preservation methods

• Published in: Revista de biología tropical Vol. 47; no. 1-2; pp. 143 - 149
• Main Author: Cressa, C
• Format: Journal Article
• Language: English
• Published: Universidad de Costa Rica 01.06.1999
• Subjects: aquatic insects; Biodiversity Conservation; Biology; Biomass; Freshwater; length-dry mass; Leptonema; Phylloicus; relationships; Thraulodes; tropics; Venezuela, Guarico, Orituco R; relationships; length-dry mass; aquatic insects; Biomass; tropics
• ISSN: 0034-7744; 2215-2075

Relationships of body mass and head capsule width were calculated for Thraulodes sp., Haplahyphes sp. (Ephemeroptera), Leptonema sp. and Nectopsiche sp. (Trichoptera), and Anacroneuria sp. (Plecoptera) using different preservatives (Freezing, formaldehyde 4% and Kahle). The organisms were collected monthly during a year on the Orituco River, Guarico, Venezuela, with a Surber net (0. 1296 m super(2) and 0.286 mm mesh size). Regression analysis indicated that all relationships were highly correlated for any of the fixative used. Changes in dry mass per unit change of head capsule width, vary among species and presevatives with no clear relationships among them. Changes in dry mass calculated as the difference between dry mass of preserved samples to those of unpreserved ones, indicate that all fixatives underestimate dry mass by as much as 85.4% except for Nectopsyche sp. whose dry mass was always overestimated. These results provide further evidence on the effect of preservatives on dry mass losses.