In mangrove ecosystems, litter fall accumulates as refractory organic carbon on the sediment surface and creates anoxic sediment layers. Fiddler crabs, through their burrowing activity, translocate oxygen into the anoxic layers and promote aerobic respiration, iron reduction and nitrification. In this study, the effects of four species of fiddler crabs (Uca triangularis, Uca rosea, Uca forcipat...

The fiddler crabs, Uca lactea, which live on intertidal mudflats, exhibit a remarkable ability to return to its burrow. It has been reported that the species usually use path integration, an ideothetic mechanism for short-range homing. During the mating season, however, the accumulation error of the process increases due to vigorous courtship movement. To compensate for this, most courting male...

Optimal escape theory generally assumes that animals have accurate information about predator distance and direction of approach. To what degree such information is available depends not only on the prey's sensory capabilities but also on its behaviour. The structure of behaviour can strongly constrain or support the gathering of information. The ability of animals to collect and process inform...

Colour changes in fiddler crabs have long been noted, but a functional interpretation is still lacking. Here we report that neighbouring populations of Uca vomeris in Australia exhibit different degrees of carapace colours, which range from dull mottled to brilliant blue and white. We determined the spectral characteristics of the mud substratum and of the carapace colours of U. vomeris and fou...

Males often produce dynamic, repetitive courtship displays that can be demanding to perform and might advertise male quality to females. A key feature of demanding displays is that they can change in intensity: escalating as a male increases his signalling effort, but de-escalating as a signaller becomes fatigued. Here, we investigated whether female fiddler crabs, Uca mjoebergi, are sensitive ...

Observations were performed to detcrminc the relationship bctwccn the time of maximal pigment dispersion in the fiddler crabs, Uca pugilator and Uca minax, and the tidal events on the beach where the crabs were collcctcd. Uca pugilator obtained from burrows above the high tide mark did not have an overt tidal rhythm but did have 24-hour and 14.8-day cycles of color change. The tidal rhythm was ...

In September 1969, the Florida barge spilled 700,000L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor (Buzzards Bay, MA). Today the aboveground environment appears unaffected, but a substantial amount of moderately degraded petroleum still remains 8-20cm below the surface. The salt marsh fiddler crabs, Uca pugnax, burrow into the sediments at depths of 5-25cm, and are chronically...