Marine Ecology. ISSN 0173-9565 ORIGINAL ARTICLE Autotomy in porcelain crabs is an effective escape mechanism from rockfish predation Matthew L. Knope1 & Ralph J. Larson2 1 Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, USA 2 Department of Biology, San Francisco State University, San Francisco, CA, USA Keywords Abstract Anti-predatory behavior; crabs; natural selection; porcellanidae; rockfish; sebastes. Porcelain crabs possess a ‘hair-trigger’ propensity to autotomize their chelipeds (claws), and laboratory studies have demonstrated that this ability is highly Correspondence effective in avoiding predation from other crabs. However, porcelain crabs are Matthew L. Knope, Department of also subject to predation from fishes, which use a very different means of cap- Geological and Environmental Sciences, ture. In this study, we investigated whether autotomy in porcelain crabs is also Stanford University, 385 Serra Mall, Stanford, effective against predation by fishes. To do this, we examined stomach-contents CA 94305, USA. data from four common species of kelp-forest rockfishes and determined the E-mail:
[email protected] frequency of disassociated chelipeds (those with no associated bodies) in porce- Accepted: 8 August 2013 lain crabs and in brachyuran crabs, which do not readily autotomize their chelipeds. We found that disassociated chelipeds of porcelain crabs were six doi: 10.1111/maec.12103 times as common as those of brachyuran crabs (35% of the remains of all por- celain crabs versus 6% of the remains of all brachyuran crabs). We interpret this difference to be evidence that, through autotomy, porcelain crabs escaped ingestion of their entire bodies, and thus certain mortality, at a higher rate than did brachyuran crabs.