Abstract
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.
Full Text
The Full Text of this article is available as a PDF (89.3 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Hansson L. A. Induced pigmentation in zooplankton: a trade-off between threats from predation and ultraviolet radiation. Proc Biol Sci. 2000 Nov 22;267(1459):2327–2331. doi: 10.1098/rspb.2000.1287. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marin F., Smith M., Isa Y., Muyzer G., Westbroek P. Skeletal matrices, muci, and the origin of invertebrate calcification. Proc Natl Acad Sci U S A. 1996 Feb 20;93(4):1554–1559. doi: 10.1073/pnas.93.4.1554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Peacor S. D., Werner E. E. The contribution of trait-mediated indirect effects to the net effects of a predator. Proc Natl Acad Sci U S A. 2001 Mar 20;98(7):3904–3908. doi: 10.1073/pnas.071061998. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rundle S. D., Brönmark C. Inter- and intraspecific trait compensation of defence mechanisms in freshwater snails. Proc Biol Sci. 2001 Jul 22;268(1475):1463–1468. doi: 10.1098/rspb.2001.1682. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Trussell G. C., Smith L. D. Induced defenses in response to an invading crab predator: an explanation of historical and geographic phenotypic change. Proc Natl Acad Sci U S A. 2000 Feb 29;97(5):2123–2127. doi: 10.1073/pnas.040423397. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Van Buskirk J., Saxer G. Delayed costs of an induced defense in tadpoles? Morphology, hopping, and development rate at metamorphosis. Evolution. 2001 Apr;55(4):821–829. doi: 10.1554/0014-3820(2001)055[0821:dcoaid]2.0.co;2. [DOI] [PubMed] [Google Scholar]