The effects of Dreissena polymorpha on Campeloma decisum's righting ability and lateral movement.

Abstract

The introduction of the zebra mussel (Dreissena polymorpha) has had major economic and ecological implications, fouling pipes and exacerbating the declines of native freshwater mollusks. This study examines the effects of D. polymorpha biofouling on the fitness of Campeloma decisum, using lateral movement and righting ability, as proxies for fitness. We collected C. decisum from Douglas Lake in Cheboygan County, Michigan, and tested them in aquaria filled with sand and lake water. We found that D. polymorpha significantly aided snail righting ability. Also, D. polymorpha was shown to both hinder and assist lateral movement, with inhibiting effects being stronger and more prevalent. To test the effect of captivity on snail behavior, an additional sample set was tested using the same methods. We found captivity did have an effect on righting ability, but did not have a significant effect on lateral movement. Our findings support previous research suggesting D. polymorpha can have positive and negative effects on C. decisum fitness (Albalak & Lamb 2005, Tucker 1994, Stewart & Haynes 1994).