Editing Fiddler crab (section)

==Ecology and life cycle ==
Fiddler crabs primarily exist upon mudflats, sandy or muddy [[beaches]] as well as salt marshes within [[mangroves]]. Fiddler crabs are found in [[West Africa]], the [[Western Atlantic]], the [[Eastern Pacific]],  [[Indo-Pacific]] and [[Algarve region]] of [[Portugal]]. 

Whilst the fiddler crab is classified as an omnivore, it does present itself as an opportunist and will consume anything with nutritional value.<ref>Zeil, J., Hemmi, J. M. & Backwell, P. R. Y. (2006). Fiddler crabs. ''Current Biology, 16''(2), 40-41. [https://doi.org/10.1016/j.cub.2006.01.012 doi: 10.1016/j.cub.2006.01.012]</ref> The crab will feed through bringing a chunk of sediment to its mouth and sifting through it to extract organic material. This crab will filter out [[algae]], [[microbes]], [[fungus]] or any form of detritus. Once finished consuming all the organic matter from the sediment, these crabs will then deposit them as small sand balls near their burrow. 

Fiddler crabs are thought to potentially act as [[ecosystem engineer]]s within their habitat due to the way they rework the sediment during feeding.<ref>Crane, J. (2015). ''Fiddler crabs of the world: Ocypodidae: genus Uca'' (Vol. 1276). Princeton University Press.</ref> Whilst these crabs do rework the sediment around them, upturning the very top layer and depositing it nearby, there is still debate that exists as to whether this turnover of sediment has any proven difference regarding nutrients and aeration of the sediment.<ref>Michaels, R. E. & Zieman, J. C. (2013). Fiddler crab (''Uca'' spp.) burrows have little effect on surrounding sediment oxygen concentrations. ''Journal of Experimental Marine Biology and Ecology, 448'', 104-113. [https://doi.org/10.1016/j.jembe.2013.06.020 doi: 10.1016/j.jembe.2013.06.020]</ref>

Fiddler crabs are a burrowing species, where within their territory they may possess several burrows. There are two types of [[burrow]]s that the fiddler crabs can build, either breeding burrows or temporary burrows.<ref>Christy, J. H. (1982). Burrow structure and use in the sand fiddler crab, ''Uca pugilator'' (Bosc). ''Animal Behaviour, 30''(3), 687-694. [https://doi.org/10.1016/S0003-3472(82)80139-5 doi: 10.1016/S0003-3472(82)80139-5]</ref> Temporary burrows are constructed by both males and females during high tide periods. These burrows are also constructed at night time when the crabs are no longer feeding and are hiding from predators. Breeding burrows are constructed by solely males, and will be constructed within the area that they have deemed their territory. These breeding burrows are constructed by male crabs  so that the female and male crabs may copulate within the burrow, and the female may deposit and incubate her eggs within this area. Larger males who can more easily defend their territory will often have multiple suitable breeding burrows within their territory to enable them to mate with multiple female crabs.<ref> Mautz, B., Detto, T., Wong, B. B. M., Kokko, H., Jennions, M. D. & Backwell, P. R. Y. (2011). Male fiddler crabs defend multiple burrows to attract additional females. ''Behavioral Ecology, 22''(2), 261–267. [https://doi.org/10.1093/beheco/arq207 doi: 10.1093/beheco/arq207]</ref> Female crabs are found to prefer to mate with males that have the widest burrows, however, [[carapace]] width and claw size does correlate with the width of the burrow, so could be a potential size bias.<ref name="Reaney">Reaney, L. T., & Backwell, P. R. Y. (2007). Temporal constraints and female preference for burrow width in the fiddler crab, Uca mjoebergi. ''Behavioral Ecology and Sociobiology, 61'', 1515-1521. [https://doi.org/10.1007/s00265-007-0383-5 doi: 10.1007/s00265-007-0383-5] </ref> 

Two types of fiddler crabs are found to exist within a given territory, a wandering female or male, and territory-holding male or females.<ref>Peso, M., Curran, E., & Backwell, P. R. Y. (2016). Not what it looks like: mate-searching behaviour, mate preferences and clutch production in wandering and territory-holding female fiddler crabs. ''Royal Society Open Science, 3''(8). [https://doi.org/10.1098/rsos.160339 doi: 10.1098/rsos.160339]</ref> When in a wandering state, this means crabs do not currently occupy a burrow. They will wander in order to look for territory which contains a burrow, or to look for a mate. Wandering females will look for a mate to [[copulate]] with, usually preferring to mate with a male that currently possesses a burrow. The female fiddler carries her eggs in a mass on the underside of her body. She remains in her burrow during a two-week gestation period, after which she ventures out to release her eggs into the receding tide. The larvae remain [[plankton]]ic for a further two weeks.

The mating system of fiddler crabs is thought to be mainly [[polygynous]], where the male crabs will mate with multiple females if they have the opportunity to, however, female fiddler crabs such as the ''Austruca lactea'' are known to also mate with multiple males.<ref>Murai, M., Goshima, S. & Henmi, Y. (1987). Analysis of the mating system of the fiddler crab, ''Uca lactea. Animal behaviour, 35''(5), 1334-1342. [https://doi.org/10.1016/S0003-3472(87)80005-2 doi: 10.1016/S0003-3472(87)80005-2]</ref> 

As they are a species of crustacean, they perform [[ecdysis]], which is the process of moulting. When crabs moult, they produce hormones which trigger the shedding of their [[exoskeleton]] and regeneration of limbs. Moulting is already an extremely stressful time for fiddler crabs, as their shell becomes extremely soft, leaving them vulnerable to predation.<ref>Guyselman, J. B. (1953). An analysis of the molting process in the fiddler crab, ''Uca pugilator. The Biological Bulletin, 104''(2). [https://doi.org/10.2307/1538787 doi: 10.2307/1538787]</ref> When undergoing this moulting cycle, crabs will frequently hide within their burrows to avoid harm. When male crabs are undergoing the moulting process, if they are exposed to other male crabs in high grouping with consistent light, their ability to regenerate limbs will be impaired.<ref>Weiz, J. S. (1976). Effects of environmental factors on regeneration and molting in fiddler crabs. ''The Biological Bulletin, 150''(1). Doi: 10.2307/1540596</ref>

Whilst the crabs major claw does function as a tool for fighting and competition, it also plays a role in [[thermoregulation]]. As the claw is so large, and these crabs live in generally hot territory, so require strategies to keep themselves cool, particularly for wandering males without burrows. The presence of the major claw upon the male helps them keep their body temperature regulated, and decreases the chance of them losing or gaining too much heat in a given time period. The large claw draws away excess body heat from the core of the fiddler crab and allows it to dissipate.<ref>Darnell, M. Z. & Munguia, P. (2011). Thermoregulation as an Alternate Function of the Sexually Dimorphic Fiddler Crab Claw. ''The American Naturalist, 178''(3). [https://doi.org/10.1086/661239 doi: 10.1086/661239]</ref> Heat is found to dissipate significantly faster when male crabs are performing waving at the same time. 

Fiddler crabs come in many different colourations and patterns, and are known to be able to change their colour over time. Fiddler crabs such as the ''[[Tubuca capricornis]]'' are capable of changing their colour rapidly when placed under significant stress.<ref>Detto, T., Henmi, J. M. & Backwell, P. R. Y. (2008). Colouration and Colour Changes of the Fiddler Crab, ‘’Uca capricornis’’: A Descriptive Study. ''PLOS ONE, 3''(2). [https://doi.org/10.1371/journal.pone.0001629 doi: 10.1371/journal.pone.0001629]</ref> When fiddler crabs undergo moulting, they are seen to have reduced colouration after each sequential moult. Female fiddler crabs are traditionally more colourful than male fiddler crabs. Conspicuous colouring in fiddler crabs is dangerous as it increases predation rate, however, sexual selection argues for brightly coloured crabs.<ref>Detto, T. (2007). The fiddler crab Uca mjoebergi uses colour vision in mate choice. ''Proceedings of the Royal Society B, 274''(1627). [https://doi.org/10.1098/rspb.2007.1059 doi: 10.1098/rspb.2007.1059]</ref> Fiddler crabs have finely tuned visual systems that aid in detecting colours of importance, which aid in selecting coloured mates.<ref>Zeil, J. & Hemmi, J. M. (2006). The visual ecology of fiddler crabs. ''The Journal of Comparative Physiology A, 192'', 1-25. {{doi|10.1007/s00359-005-0048-7}}</ref> When given the choice, females prefer to pick males that are more brightly coloured in comparison to dull males.