Document Type

Article

Publication Date

2002

Abstract

Walking and swimming are the most common forms of locomotion used routinely by decapod crustaceans, but some have evolved ways of locomoting throughsubstrates, notably sand. Two such digging species, of different infraorders, are spanner crabs (Ranina ranina; Brachyura) and spiny sand crabs (Blepharipoda occidentalis; Anomura). Videotape and electromyogram analysis showed that digging by these species is similar, but Raninahas a wider locomotor repertoire than Blepharipoda: for instance, Raninacan walk forward on the benthos, whereas Blepharipoda(and other sand crabs) cannot walk. Similarly, although both Raninaand Blepharipodadig into the sand using their legs and abdomen, leg movements of Raninaare less stereotyped than those of Blepharipoda. In both species, the second and third pairs of legs shovel sand forward from underneath the animals, while the fourth pair of legs circles in the opposite direction, forcing the posterior end of the animals down into sand. Both species show similar patterns of contralateral leg coordination: left and right legs move forward and backward alternately when above sand, but switch to bilateral synchrony when they begin to submerge into sand. The abdomen is also rhythmically active during digging in both species, even though the abdomen is relatively stiff in Ranina. Thus, Raninais behaviourally intermediate to the highly specialized digging anomuran sand crabs (e.g., Blepharipoda) and more common walking decapod crustaceans (e.g., crayfish).

Publication Title

American Zoologist

Included in

Biology Commons

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.