Eric Sanford and David J. Worth. 2009. Genetic differences among populations of a marine snail drive geographic variation in predation. Ecology 90:3108–3118.

Appendix C. A table showing the effect of source of mussels on snail drilling capacity.

Notes: Test of whether the geographic source of mussels influenced the frequency of predation on Mytilus californianus by snails (Nucella canaliculata) from Oregon. Three family lineages of F2 snails (A, B, C) from Oregon sites (SH or FC) were tested. For each lineage, 24 sibling snails were raised to adult size (18–25 mm long) on a common diet of M. trossulus. The snails in each lineage were then placed in independent 1-L containers (one snail per container) and were randomly assigned to one of two treatment groups. Snails in one group were provided 50–70 mm long mussels collected from California (BH), whereas the other group received similarly sized mussels from Oregon (SH). Snails were scored for their ability to drill M. californianus during a 100-day trial. The frequency of Oregon snails drilling M. californianus was low, regardless of the source of mussels. The only mussels drilled in this trial originated from California, indicating that using mussels from a common source in California did not bias the results of our full scoring experiment (see Fig. 2).