Appendix C. Model selection summary for analysis of snail behavior.
TABLE C1. Model selection summary for analysis of snail behavior, which was based on density of snails observed on cordgrass leaves during ebb tide. Fitted parameters include (a) intercept, (b) tidal regime, (c) identity of specific predator and its cue, (d) presence of any predator or predator cue, (e) day, and (f) first or second portion of the experiment. AIC difference (Δ_{i}) is the difference between the AIC_{c} of model i and the lowest AIC_{c} observed. Akaike weight (w_{i}) is calculated as the model likelihood, exp(-Δ_{i} / 2), normalized by the sum of all model likelihoods; values close to 1 indicate greater confidence in the selection of a model.
Behavior models | df | (Δ_{i}) | w_{i} |
a | 4 | 43.4 | < 0.001 |
b | 5 | 34.5 | < 0.001 |
c | 5 | 45 | < 0.001 |
d | 6 | 46.4 | < 0.001 |
e | 5 | 48 | < 0.001 |
f | 5 | 45.7 | < 0.001 |
b + c | 6 | 38.3 | 0.001 |
b + d | 7 | 32.2 | < 0.001 |
b + e | 6 | 34 | < 0.001 |
b + f | 6 | 33.9 | < 0.001 |
c + e | 6 | 44.5 | < 0.001 |
c + f | 6 | 42.2 | 0.998 |
d + e | 7 | 40.4 | < 0.001 |
d + f | 7 | 38.1 | < 0.001 |
b + c + e | 7 | 37.9 | < 0.001 |
b + c + f | 7 | 35.6 | < 0.001 |
b + d + e | 8 | 34.3 | < 0.001 |
b + d + f | 8 | 32.0 | < 0.001 |
b × c | 7 | 39.2 | < 0.001 |
b × d | 9 | 28.4 | < 0.001 |
b × e | 7 | 32.5 | < 0.001 |
b × f | 7 | 24.1 | 0.001 |
c × e | 7 | 46.4 | < 0.001 |
c × f | 9 | 41.5 | < 0.001 |
d × e | 9 | 32.7 | < 0.001 |
d × f | 11 | 35.7 | < 0.001 |
b × c × e | 11 | 23.4 | < 0.001 |
b × c × f | 15 | 15.1 | < 0.001 |
b × d × e | 15 | 0.0 | 1.0 |
FIG. C1. Mean (± SE) number of snails observed on cordgrass leaves during low tide for (i) diurnal tidal schedule with specific and unrestrained predators; (ii) diurnal tidal schedule with specific predator cues; (iii) mixed semidiurnal tidal schedule with unrestrained predators; and (iv) mixed semidiurnal tidal schedule with predator cues. Cordgrass and snails (open bars); cordgrass, snails and conch (or conch cue; light gray bars); cordgrass, snails and crab (or crab cues; gray bars), cordgrass, snails and both predators (or both predator cues; dark gray bars).