Influence du sulfate de cuivre sur la structure du filet des larves d'Hydropsyche (Insecta, Trichoptera)

Abstract

Copper sulphate with an initial concentration as low as 125 µg Cu/l in hard water adversely affects the capacity of the larvae of Hydropsyche to spin nets. The irregularity that is first apparent is the high number of thread-interruptions. At higher concentration, the number of meshes per net decreases.A typical anomaly of the toxic action of copper is the deposition of threads as cotton like harks instead of net tissues. The symetry and regularity of the meshes in the catching area is only slightly affected by copper. This contrasts strikingly with the effects of a carbamate insecticide studied earlier.The primary site of the action of cooper seems to be the silk gland and not the nervous system as is the case with the above pesticide.The findings in the laboratory confirm those made in the field. Concentrations which severely impair net construction are prohibitive for occurence in nature. The Hydropsyche-test requires only short test-times and simple equipment and yet gives information on long term effects. © 1979 Masson.