In this study we tested the effect of population density on agonistic interactions in male Uca leptodactyla Rathbun, 1898. We recorded the crab’s behaviour in pairs or in groups of five animals composed of conspecifics and heterospecifics living in the same area (sympatric) and distinct areas (allopatric) of the mangrove forest. Allopatric conspecific crabs showed higher approaching and signalling than those in other conditions. The higher the crab density, the lower the interaction intensity between animals. Low-level agonistic signals were mainly displayed in high density (groups), while claw touch mainly occurred in pairs. Allopatric conspecifics showed the more intense agonistic interactions. Therefore, Uca seems to decrease energy investment in unnecessary fights against sympatric and conspecific crabs. Population density is a major factor driving agonistic behaviour mainly when conspecific animals are kept together. This may occur due to the increased competition for the same resources.
Density-dependent influence of male characters on mate-locating efficiency and pairing success in the waterlouse Asellus aquaticus: an experimental study.
Journal of Zoology,
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Population structure of the fiddler crab Uca leptodactyla Rathbun, 1898 (Brachyura: Ocypodidae) in a tropical mangrove of northeast Brazil.
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Morphological adaptations of the second maxilliped in semiterrestrial crabs of the genus Uca Leach, 1814 (Decapoda, Ocypodidae) from a subtropical Brazilian mangrove.
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When and why do territorial coalitions occur? Experimental evidence for factors that promote territorial coalitions in fiddler crabs.
The American Naturalist,
Simple, multiple and joint correspondence analysis. R package version 0.33, available online athttp://CRAN.R-project.org/package=ca. (R Foundation for Statistical Computing, Vienna).
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Effects of environmental colour on growth of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) housed individually or in groups.
Journal of Applied Ichthyology,
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Burrow morphology of Uca uruguayensis and Uca leptodactylus (Decapoda: Ocypodidae) from a subtropical mangrove forest in the western Atlantic.
A comparison of alternative methods for estimating population density of the fiddler crab Uca annulipes at Saco Mangrove, Inhaca Island (Mozambique).
MansfieldC., 2009. The effects of density on intraspecific aggression in the fiddler crab, Uca crassipes, on Mo’orea, French Polynesia. UCB Moorea class: biology and geomorphology of Tropical Islands, available online at http://escholarship.org/uc/item/2jz4s7z8.
Distribution and abundance of fiddler crabs Uca Leach (Crustacea Decapoda Ocypodidae) in Guaratuba Bay, Parana State, southern Brazil.
Revista Brasileira de Zoologia,
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Population density and the intensity of sexual selection on body length in spatially or temporally restricted natural populations of a seed bug.
Behavoral Ecology and Sociobiology,