Trade-off between mating and predation risk in the marine snail, Littorina plena
We investigated the hypothesis that predation risk affects mating decisions in the intertidal snail Littorina plena in Bamfield Inlet, Northeast Pacific. First, we conducted a field tethering experiment to test the assumption that mating pairs of snails are more susceptible to predation than solitary individuals, and then performed a laboratory experiment to quantify the effect of predation threat on the propensity of snails to form mating pairs. Our results support the hypothesis, in that “mating pairs” were more frequently killed than single snails in the field, and snails were less likely to form mating pairs in the laboratory when simulated predation risk was high (chemical cues from crushed conspecifics were added to the water) than when it was low (no risk cues were added to the water). In contrast to several earlier studies, we found no effect of individual size on snail susceptibility to predation, perhaps because our two size classes were contiguous and snails within them were not dissimilar enough. The results of the behavioral experiment were consistent with this lack of individual size effect on snail vulnerability; both size classes of snails showed a significant and similar tendency to decrease mating when predation risk was high. Taken together, the results of this and recent studies indicate that predators can considerably affect the behavior of littorinid snails, including their movement patterns, feeding, and reproduction. We argue that greater consideration should be given to how marine invertebrates trade off predation risk and activities related to reproduction.
Document Type: Research Article
Affiliations: Biology Department, University of New Brunswick, Saint John, New Brunswick, Canada E2L 4L5, and Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada V0R 1B0
Publication date: October 1, 2007