Decalcification of a clam shell caused by trematodes: side effect or manipulation of the host phenotype?
A. E. ZHOKHOV1, M. N. PUGACHEVA1, V. N. MIKHEEV2
1Papanin Institute for Biology of Inland Waters RAS, Borok, Russia
2A. N. Severtsov Institute of Ecology & Evolution RAS, Moscow, Russia
Keywords: manipulation of phenotype, clam Pisidium, trematodes, Allocreadium crassum
Abstract
Changes in the total weight of live clams Pisidium amnicum and weight of their shells were studied by comparing uninfected clams with clams infected with trematods Allocreadium crassum, Phyllodistomum folium and Bunodera spp. Mean total and shell weights of clams infected with A. crassum were significantly lower than those of uninfected clams. Characteristics of clams infected with P. folium and Bunodera spp. were not different from the control with the exception of the weight of clams infected with Bunodera spp. Clams infected with mature metacercariae of A. crassum possessed light and fragile shells that weighed on average 3 times less than those of uninfected clams (25.6 vs 74.1 g.). The weight of shells of clams with immature metacercariae was not different from that of uninfected clams. The obtained results were analyzed from the viewpoint of the hypothesis of adaptive manipulation of the host phenotype.
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