Morphology, distribution and desiccation in the brown garden snail (Cantareus aspersus) in northern New Zealand

Size, density and distribution of the brown garden snail (Cantareus aspersus) were observed relative to cover at a coastal reserve on the North Island, New Zealand. Cover variables depended on vegetation height and available debris (rubbish, wood, cow dung). Air temperature, ground temperature, and relative humidity were recorded continuously during the field survey for the various cover types. Live snails used debris disproportionately as resting habitat, where relative humidity and temperature were the least variable. Desiccation rates were obtained by dehydrating snails of three size-classes and calculating desiccation rates as a function of water loss over time under controlled conditions in the laboratory. Results suggest that the shell aperture:size ratio is an important factor regarding desiccation stress in C. aspersus, especially in young and small-sized snails.