Soldier crabs Mictyris guinotae exhibit pronounced swarming behaviour. The swarms of the crabs tolerant of perturbations. In computer models and laboratory experiments we demonstrate that swarms of soldier crabs can implement logical gates when placed in a geometrically constrained

total of 35 species of leucosiid crabs have been recorded by several authors and the current survey from the persian gulf. here, zoogeography of these species and their zoogeographical affinities within indo-west pacific region are discussed. in addition, present taxonomic survey off the iranian coasts of the persian gulf resulted in finding 14 leucosiid crabs, of which arcania erinacea and par...

Adult female crabs (Potamonpersicum; n=65) were collected from the Jajrood River in the east of Tehran, Iran. Both eyestalks were removed in crabs that weighed 27.6 ± 2.1 g. Changes in the levels of glucose and protein titers in the hemolymph, the number of hemocytes, gonadal and hepatic indices, body weight and carapace length were determined. The level of glucose in the hemolymph was signific...

The parasitic dinoflagellate Hematodinium sp. parasitizes blue crabs along the Atlantic seaboard of the United States. Infections in blue crabs have only been reported from waters where salinity is >11 practical salinity units (psu). Blue crabs maintain a hyperosmotic internal concentration at low salinities (0-5 psu), roughly comparable to 24 psu, and should be capable of maintaining an infect...

A manned submersible was used in a fjord in southeastern Alaska to study the distributional patterns of the red king crab (Paralithodes camtschaticus) and the Tanner crab (Chionoecetes bairdi) in summer. The cove was divided into three zones: inner, middle, and outer. Six types of habitats, including sand-mud, rock, shell, debris, rock wall, and algae, were identified from video tapes. A relati...

Juvenile Dungeness crabs spend ~1 year in the San Francisco Estuary, where they undergo considerable growth before returning to the coastal ocean. Previous studies suggest that competition, food scarcity and avoidance of conspecifics may cause some juvenile Dungeness crabs in the San Francisco Estuary to become food limited. Food limitation may force these crabs to forage in higher temperature ...

Both the need for shelter and the need for food can be motivations that alter animal behaviour. We tested the hypothesis that the hermit crab, Pagurus samuelis, deprived of food, shells, or both will respond differently from control hermit crabs when presented with food and shells concurrently. We measured the number of contacts made with both food and shells, and time elapsed until hermit crab...

Beyond their commercial importance for LAL and bait, and their status as a living fossil, it is often asserted that horseshoe crabs play a vital role in the ecology of estuarine and coastal communities. How would the various ecological relationships involving horseshoe crabs be affected if these animals were no longer abundant? Attempts to understand and generalize the ecological importance of ...

Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected the foraging behavior of the green crab (Carcin...

Amphibious crabs, Cardisoma guanhumi, were acclimated to breathing either air or water and exposed to altered levels of oxygen and/or carbon dioxide in the medium. Hypercapnia (22, 36 and 73 torr CO(2)) stimulated a significant hypercapnic ventilatory response (HCVR) in both groups of crabs, with a much greater effect on scaphognathite frequency (Deltaf(SC)=+700%) in air-breathing crabs than wa...