Print PagePhenotypic plasticity has long been thought to underlie the ability of a species to colonize new environments or communities and become invasive--geographically widespread and ecologically dominant. Here we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, P. antipodarum, isolated from the US, (one invasive and one not yet invasive) with that of two species of native snails, Fossaria bulimoides group and Physella gyrina. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) and also raised them at two different temperatures (16° C and 22°C). Growth rate and mortality were measured over the course of 8 weeks.
Results/Conclusions
A preliminary analysis of the data suggests that mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and the invasive clone of P. antipodarum appears to have a lower mortality rate than the not yet invasive clone. The reaction norms to temperature of the growth rates suggest that P. antipodarum possesses a flatter reaction norm than both native species. In the conductivity experiment, reaction norms were relatively flat for all species. Little difference was found between the two clones of P. antipodarum.
