Factors affecting individual body weight in field populations of the mudsnail Hydrobia ulvae

Publisher Website
Google Scholar
Abstract
Differences in average body size among allopatric and sympatric populations of hydrobiid mudsnails have been interpreted as the consequence of interspecific competitive interactions. Recently, however, doubts have been expressed concerning the certainty with which size differences can be ascribed simply to character displacement. Other environmental factors are known to influence body size in hydrobiids. In the present study one of these, sediment type, was investigated.Average body weight of Hydrobia ulvae (Pennant) living on fine mud was consistently higher than that of members of the same species living on adjacent muddy sand. Snails were transplanted from one sediment type to the other, confined within cages, and their growth rates compared with those of control animals caged on their native sediment. The results of this experiment suggested that substrate type is one factor controlling body size, but the inconclusive nature of the results indicate that others are also involved.