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Uca thayeri M. J. Rathbun, 1900
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Family: Ocypodidae
Atlantic mangrove fiddler
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Bocas Species Database Habitat: This species favors habitats such as muddy banks of mangrove-bordered estuaries and streams. Distribution: This crab species has been reported from Western Atlantic to Florida, the West Indies, and from Mexico to Brazil. Natural History Notes: The activity of fiddler crabs is related to the tides. At low tides, the crabs stay in their burrows, but during the low tides, the crabs open their burrow and reach the surface to feed, clean their burrow and to undergo courtship. It is possible to distinguish the burrows of the ovigerous females, because they build mud chimneys on their burrows. Characteristics: This species has a carapace of 1.9 cm long. The color pattern consists of a brown to orange carapace and major claw. The major claw is long and the lower finger is slightly bent downward. Fiddler crabs (genus Uca) present easily recognizable sexual dimorphism. The males have one very large claw (major claw) that is used to undergo a characteristic wave to attract females or to defend its territory. The females do not posess such a large claw. Also, the males usually have more conspicuous colors and they are larger than the females. SummaryLeptuca thayeri, known generally as the Atlantic mangrove fiddler crab or mangrove fiddler, is a species of true crab in the family Ocypodidae. It is distributed all across the Western Atlantic. EcologyLiving on and within the sediments of mangrove trees, this fiddler crab has an ecological importance. The fiddler crab influences the structure and biology of the sediment through foraging and by constructing burrows for defense. The fiddler crab, Leptuca thayeri, influence bacterial assemblages in the sediment surrounding the mangrove trees they inhabit by decreasing bacterial diversity through foraging. While foraging, these fiddler crabs divide out the individual sediment grains with their spoon-tipped setae. This division of sediment grain allows for the bioturbation of sediments which allows oxygen penetration at depth and remineralization of organic matter. Fiddler Gelasimus vomeris, a related member to the Leptuca thayeri.Reproductive behaviorsPerhaps the most widely studied aspect of the mangrove fiddler crab is its unique reproductive behavior. When studied broadly, the U. thayeri resembles a "broad front" fiddler crab, which describes the spacing of the eye stalks. This appearance, usually indicates that the individual crab would have resource-based mating system, while in fact, the mangrove fiddler crab exhibits the opposite, which is a resource-free mating system. This switch in behavior has been best described as an evolutionary convergence of reproductive behaviors between the "broad" and "narrow" front crabs. Another aspect to the reproductive behavior of U. thayeri is the hatching time of larval crabs in relation to the tide. In this species, it has been determined, regardless of whether the tides are semi-diurnal or mixed, larval crabs will be released after high tide, when the light-dark cycle and tidal amplitude are most... |
