Daily activity pattern of Heleobia parchappii (Gastropoda: Hydrobiidae) under laboratory conditions

Abstract

Crawling, floating and burrowing abilities of the Argentine freshwater mudsnail, Heleobia parchappii (d?Orbigny 1835), were experimentally analyzed. Floating showed a cyclic circadian pattern, young snails using floatation more frequently than adults; males and females did not show a differential use of a floating escape strategy. Though males of freshwater prosobranchs are expected to be more active than females as an adaptive outcome of reproductive fitness, crawling velocity of Heleobia parchappii did not differ significantly between sexes, but males were effectively more active than females on an activity-time allocation basis.