Original paper

Relationship between pollution and fluctuating asymmetry in the pollution-tolerant caddisfly Hydropsyche exocellata (Trichoptera, Insecta)

Bonada, Núria Vives; Rieradevall, Maria; Prat, Narcís

Abstract

Most methods of water quality evaluation focus on the community level using order, family or species, but few address the population or individual level. We studied whether larval fluctuating asymmetry (FA) observed in Hydropsyche exocellata is related to deterioration of water quality downstream in a Mediterranean river ecosystem greatly affected by urban and industrial activities. FA levels increased downstream in all traits measured, indicating that the selection of a few traits would suffice in FA studies related to environmental conditions. However, downstream changes differed in the first, second or third leg. Pearson correlations revealed a strong positive relationship between FA and chloride, conductivity and suspended solids for almost all traits, and between FA and phosphates only for the second leg traits. The study of FA in a pollution-tolerant macroinvertebrate such as H. exocellata may be a useful method to assess global water quality in Mediterranean rivers. Our study emphasizes the use of FA as an early warning technique to prevent the disappearance of species in ecosystems subjected to environmental stress.

Keywords

fluctuating asymmetrymediterranean riverswater qualitytrichoptera