Evol Ecol Res 9: 579-597 (2007)     Full PDF if your library subscribes.

Geographic correlation between reciprocally adaptive traits of an exotic decapod predator and native gastropod prey: evidence of an arms race?

Timothy C. Edgell* and Rémy Rochette

Department of Biology, University of New Brunswick, 100 Tucker Park Road, PO Box 5050, Saint John, NB E2L 4L5, Canada

Author to whom all correspondence should be addressed.
e-mail: tim.edgell@unb.ca


Question: Is there evidence of an arms race between the predatory crab Carcinus maenas and herbivorous snail Littorina obtusata in the northwest Atlantic?

Data description: We compared crab claw volume (both master/crusher and minor/handler claws of males and females) and snail shell mass, standardized for a range of predator and prey body sizes, across 26 sites in the Gulf of Maine and Bay of Fundy.

Search methods: We assessed geographically based correlations between (i) crab master claw volume and snail shell mass, (ii) crab minor claw volume and shell mass, and (iii) latitude and phenotype of both crabs and snails. The size-dependency of these relationships was explored by first using population-level regressions to estimate armament sizes for crabs and snails of different body sizes (10th to 90th percentiles), and then using these phenotypic estimates to test for changes in interspecific and latitudinal trait correlations with increasing body sizes.

Conclusions: Size-standardized snail shell mass and crab master claw volume are positively correlated to one another, and the strength of these correlations increases with increasing body size of combatants. We interpret these results as evidence of a size-dependent antagonistic interaction, and possibly an arms race, between C. maenas and L. obtusata in the northwest Atlantic. These correlations do not appear strictly due to environmental confounds (e.g. temperature), because trait correlations involving snail shell mass and crab minor claw size are substantially weaker and generally insignificant, as are those involving latitude and predator or prey size-standardized trait.

Keywords: arms race, biogeography, Carcinus, Littorina, predator–prey.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2007 Timothy C. Edgell. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.