Hermit crabs

Hermit crabs are crustaceans that live in the wild in the western Atlantic. They mate on land near the sea, and once the eggs develop, the female carries the eggs on her abdomen to the sea and leaves them on wet sand or a wet rock for the tide to carry out to sea. There are usually 1,000 to 50,000 eggs at a time. At sea, the crabs are small larvae that molt several times in order to grow to adulthood. At the adult larvae stage, the hermit crabs begin looking for a shell to live in, and once it finds a suitable shell, it lives on land for the rest of its life. They grow on land by shedding their exoskeleton. In the wild, hermit crabs can live up to 25 or 30 years. Hermit crabs are scavengers with a strong sense of smell. They are nocturnal. Hermit crabs are considered ideal for research into decision-making. When an animal stops performing one activity, it must decide what activity to perform next; this is called a "decision point." At any given time, causal factors for several different potential activities are likely to be present, and the question arises as to how the ani

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ed in an aversion to the altered shells by hermit crabs. This suggested that the crabs select shells on the basis of several shell traits bearing on protection provided by the shell or by the ease with which the shell can be carried (Conover, 1978, 131-142). Mesce (1993) examines the shell selection behavior of two closely related hermit crabs, Pagarus samuelis and Pagarus hirsutiusculus. Each species showed a different preference for either Tegula funebralis shells (in the case of P. samuelis) or Nucella canaliculata shells (for P. hirsutiusculus). These shells differ greatly in their external appearance and their internal configuration. Pagarus samuelis relied on visual cues for shell selection, and this species also displays visually-mediated tracking of objects resembling the shell of choice in terms of color, shape, and size. Pagarus hirsutiusculus, on the other hand, did not show this tracking behavior. Both types of crab responded to the chemical composition of the shells, especially to the calcium content, and the application of various coatings was tried to remove the calcium from the cover of the shell. Once this cue was removed, Pagarus hirsutiusculus alone did not begin shell exploratory behavior. Both specie
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Harvey Colasurdo, Petersburg Florida, , Elwood Neil, hermit crabs, Colasurdo EA, References Conover, Mesce KA, pagarus hirsutiusculus, Biology Ecology, hermit crab, pagarus granosimanus, Neil SJ, shell selection, shell food availability, food availability, shell food, effects shell, conover 1978, effects shell food, delay metamorphosis, Tampa Bay, experimental marine biology, shell selection behavior, harvey colasurdo 1993,
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