Environmental calcium modifies induced defences in snails.
Inducible defences are adaptive phenotypes that arise in response to predation threats. Such plasticity incurs costs to individuals, but there has been little interest in how such induced traits in animals may be constrained by environmental factors. Here, we demonstrate that calcium availability interacts with predation cues to modify snail shell growth and form. Small snails increased their growth and were heavier when exposed to fish chemical cues, but this response was calcium limited. There was also an interactive effect of fish cues and calcium on the shell growth of larger snails, but shell strength and aperture narrowness were affected by calcium alone. For small snails, behavioural avoidance was greatest for snails exhibiting least morphological plasticity, suggesting a trade-off. There was no trade-off of somatic growth with plasticity. We suggest that the expression of defensive traits in molluscs can be constrained by calcium availability, which has implications for molluscan ecology and evolution.
Rundle
Simon D
SD
School of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK. srundle@plymouth.ac.uk
Spicer
John I
JI
Coleman
Ross A
RA
Vosper
Jo
J
Soane
Julie
J
D000704:Analysis of Variance; D000818:Animals; D001837:Body Weights and Measures; D002118:Calcium / Q000494:pharmacology*; D003463:Cues; D009043:Motor Activity / Q000187:drug effects*; D012908:Snails / Q000187:drug effects* / Q000254:growth & development; D006113:United Kingdom
D002118:Calcium