Jennifer Dawe

TITLE: Decoration in Hyas araneus

Dawe. J. (2007) ABSTRACT
The Newfoundland decorator crab, Hyas araneus, uses seaweed and sessile animals to decorate its body, effectively masking its shape and smell from predators. The purpose of this study was to determine if: Hyas was selective for species used for decoration, redecoration altered with previous habitat, and a canopy of seaweed altered its decorating behaviour. Hyas crabs were collected in the field from Bonne Bay and Tappers Cover from shallow waters, deep waters, and kelp beds. They were examined in the lab for initial decoration, then for redecorating behaviours in varying seaweed concentrations and with and without a seaweed canopy. Results show that it is an opportunistic decorator, or generalist, using materials readily available to it in its habitat. Initial examination of the decoration revealed a higher percent coverage for Hyas specimens collected from the kelp beds than both deep and shallow water, relating to the higher availability of decorating material. There was no change in decoration from Bonne Bay, on the west coast of Newfoundland, to Tappers Cove, on the east coast of Newfoundland. Redecoration was initially higher in shallow water specimens, but leveled out with increased seaweed concentrations, indicating that original habitat characteristics influenced the specimens. There was a significant difference between decoration under a canopy versus no cover with increased seaweed concentration, however no significant difference for the individual variables of canopy or decoration. This indicated a complex relationship between seaweed abundance and kelp bed canopy.

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