Quantifying colour patterns on the black carapace of the fiddler crab Uca capricornis
Fiddler crabs are often spectacularly coloured and capable of dramatic colour changes. While the adaptive significance of variation resulting from short- or long-term colour changes is generally well known, the phenotypic diversity in colour pattern between individuals is often neglected. To fully understand the development and function of colour pattern variation, it is necessary to first describe its morphological basis and the naturally occurring diversity. - NB Colour pattern refers to the configuration of any coloured areas on the black carapace, regardless of their spectral composition.
During this experiment 276 fiddler crabs of the species Uca capricornis were photographed - 117 females and 159 males. Using these pictures and a host of software programs, images were constructed that illustrate the probable colour patterns of various groups of crabs, including males and females in general, and males and females with various size classes; <8mm, 8-9.9mm, 10-11.9mm, 12-13.9mm, 14-15.9mm, 16-17.9mm, and males >18mm (no photographed females were >18mm). These images are the equivalent of an average crab's colour pattern.
To more clearly illustrate the variation in colour pattern between the groups, similar images were constructed using the standard deviation of crabs coloured at each coordinate (1mm x 1mm square).
Data and resources
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MethodologyDOC Open
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The probable colour patterns of various size groups of Uca capricornisDOC Open
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Variation in the probability that a particular area of the carapace is colouredDOC Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 1ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 2ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 3ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 4ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 5ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 6ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 7ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 8ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 9ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 10ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 11ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 12ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 13ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 14ZIP Open
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Zipped folder containing photos of individual crabs and the associated warped image: Folder 15ZIP Open
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Additional information
| Date (publication) | 2007-08-15 |
|---|---|
| Status | completed |
| Update frequency | asNeeded |
| Metadata language | en |
| License | Thumbnail may not be reproduced without consent from the principal investigator |
| Source metadata | ISO 19115 XML |
| Last updated | 2026-11-05 |
| Created | 2026-11-05 |
| API | package_show |