Feeding behaviour of fifteen species of hermit crabs (Crustacea: Decapoda: Anomura) from the Otago region, southeastern New Zealand

Summary

The feeding behaviour of 15 species of hermit crabs from four families (Pylochelidae, Diogenidae, Paguridae and Parapaguridae) and from habitats ranging from rocky intertidal through continental shelf gravelly sediments to finer sediments on the shelf edge and continental slope, is described.

Feeding mechanisms found include various methods of deposit-feeding, browsing, suspension-feeding, predation and scavenging. Each species employs one or two primary feeding mechanisms but also a number of secondary mechanisms. Depositfeeding techniques include scooping up detritus-rich sediment, scrubbing detritus from the surface of small granules, scraping it from larger surfaces, picking it out of crevices and other irregularities, and brushing out and ingesting material which adheres to the general body setation. A few species browse on algae and sedentary colonial invertebrates which they slice or pluck off with the chelae. A number of species filter particles out of suspension using either the general setation of the body and/or specially modified appendages which are swept through the water. Predators either capture and ingest small organisms they encounter more or less accidentally, or actively search for prey. The latter include two species which excavate pits in the sediment in search of burrowing invertebrates. All the species studied fed upon carrion although some fed much less readily than others.

Feeding behaviour in the species studied is discussed in relation to their morphology and habitat. Previously published work on feeding in hermit crabs is reviewed. It is concluded that the broad range of feeding techniques shown by most species is probably of adaptive significance as it enables the crabs to deal with a variety of different foods and substratum types.