The Invasive New Zealand Mud Snail (Potamopyrgus antipodarum) Grows Faster When Consuming Periphyton Compared to Detritus

Diet can play an important role in invasion success. The New Zealand mud snail (Potamopyrgus antipodarum) has invaded lakes and streams on four different continents. The snail has been established in the Laurentian Great Lakes since at least 1991 and has recently been discovered in stream habitats adjacent to the lakes. The purpose of this experiment was to examine the effect of a change in diet from a benthic diet of detritus to a diet dominated by periphyton on the growth rate of this snail. Juvenile snails were placed into one of four treatments: standard lab diet of Spirulina, benthic sediment (detritus), rocks with periphyton growth, or detritus and rocks with periphyton growth. The growth rate was determined after six weeks. The results demonstrated that diet greatly influences growth rate of P. antipodarum with a diet of periphyton resulting in the highest growth rate and a detritus diet resulting in the slowest rate. These results provide evidence that the movement of the snail into lotic waters where periphyton is in greater abundance in the Great Lakes region could result in faster individual and, possibly, population growth rates.