Behaviors of the pelagic red crab Pleuroncodes planipes (Decapoda: Anomura: Galatheidae) observed in captivity

Abstract

Little is known about the typical behaviors of the pelagic red crab Pleuroncodes planipes (family Galatheidae). The crabs were observed in an aquarium to determine the typical repertoire of behaviors. An activity budget was developed to address two important questions: 1) how important are locomotory behaviors among overall red crab behavior; and 2) what additional non-locomotory behaviors comprise the behavioral repertoire of red crabs. Locomotory behaviors executed by the crabs were only 15% of the total observed behaviors and were divided into active (90.4%) and passive (9.6%), or benthic (41.9%) and water column (58.1%) components. Active locomotory behaviors included “power swimmin,” “hovering,” “walking” and “climbing,” while “sinking slowly” was the only passive behavior. The crabs spent nearly 79% of their time in feeding and grooming their exoskeleton and 6.1% interacting with other crabs. The locomotory behaviors of captive red crabs are correlated well with in situ observations where they feed on planktonic organisms in the surface waters during early stages of their life, alternately swimming to the surface and sinking down in the water.