Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Predators of Pagurus
Student Author(s): Cook, Robert T.
Pages: 24
Location: Final Papers Biology 175H
Date: June 1965
Keywords: hermit crab
Abstract: 1) Under lab conditions hermit crabs were preyed upon by Cancer antennarius, C. productus, C. gracilis, Pycnopodia helianthoides, Pisaster ochraceous, and Octopus apollyon. In the field Pisaster ochraceous and Evasterias trochelii were found preying on Pagurus. 2) Cancer antennarius in the lab was oberserved to have a specific behavior for capturing and retaining Pagurus. After which the shell was examined and later cracked by varied techniques using both of the crabs pincers. Once the Pagurus was exposed from the cracked shell the maxillapeds helped extract the hermit crab and push it towards the mouth. 3) Pisaster ochraceous and oftentimes Pycnopodia helianthoides when unable to extract the Pagurus whole will insert their stomach into the shell and digest the Pagurus. 4) Pagurus in lab tanks reacted to the mere presence of a moving Pycnopodia helianthoides and showed and escape response to the Pisaster ochraceous after capture.