Length–dry mass relationships for a typical shredder in Brazilian streams (Trichoptera: Calamoceratidae)

Abstract

The aims of this study were to determine which linear body dimensions are best suitable and which mathematical functions can be used to describe length–dry mass relationships for a population of Phylloicus sp. (Trichoptera: Calamoceratidae) larvae. We measured three linear body dimensions (body length, head capsule width and interocular distance) of 54 larvae to use as dry mass predictors. For the description of length–dry mass relationships we used linear, exponential and power function models. Body length provided the best fitted equations to estimate biomass, followed by head capsule width and interocular distance. The highest coefficients of determination were found in power function and exponential models. These relationships can be useful to determine the growth rate and/or secondary production of Phylloicus larvae in future laboratory experiments, as well as to understand the importance of these shredders in the energy flux of shaded tropical streams.

Keywords:

• size-mass equations
• biomass estimation
• linear body dimensions
• Phylloicus
• tropical shredders

Acknowledgements

This study was supported by FAPEMIG, IEF-MG, CoPASA, CNPq, CAPES, Eawag, US Fish and Wildlife Service. We appreciated the help of our laboratory colleagues Lurdemar Tavares and Juliana França during field and laboratory activities. We are also thankful to João José Leal, Leandro Oliveira, Vicenç Acuña and two anonymous reviewers who provided useful comments on the manuscript.