The Influence of Biotic Stresses on the Heart Rate of Duck Mussels (Mollusca, Bivalvia, Unionidae, Anоdontinae)

Abstract

The paper deals with the influence of “gill pregnancy”, the presence of epioiks (larvae of the European bitterling Rhodeus sericeus amarus (Bloch, 1782)) and endoparasites (sporocysts and cercariae of the trematode Rhipidocotyle companula Dujardin, 1845), on the heart rate of the duck mussel Anodonta anatina (Linnaeus, 1758). The results of investigations show that biotic stresses, depending on the level of their expressiveness, put a pressure on the organism of A. anatina, thereby influencing its status, especially in what concerns the heart rate. Intensive “gill pregnancy”, high infestation level of the gills by epioiks, and total colonization of the gonads by parasites result in the development of bradycardia. The moderate influence of these factors on the mollusks is accompanied by tachycardia, which is a defense response aimed to support the viability of these animals at the optimal level.

Keywords

• Anodonta anatinа
• “gill pregnancy”
• European bitterling larvae
• Rhipidocotyle companula trematode
• heart rate