Chimney Building by Male Uca formosensis Rathbun, 1921 (Crustacea: Decapoda: Ocypodidae) after Pairing: A New Hypothesis for Chimney Function

* To whom correspondence and reprint requests should be addressed. Some crabs (and other crustaceans) build structures (pillars, hoods, chimneys, etc.) next to their burrows (Powers and Bliss 1983). Some of these structures have been shown to function for sexual attraction, e.g., pillars (Uca: Christy 1988a b), hoods (Uca: Zucker 1974 1981, Christy et al. 2002 2003), mudballs (Uca: Oliveira et al. 1998), and pyramids (Ocypode: Linsenmair 1967, Hughes 1973); some are related to disturbance (fighting or burrow occupation) caused by neighbors, e.g., hoods (Uca: Zucker 1974 and Cleistostoma: Clayton 1988), chimneys (Uca: Salmon 1987, Wada and Murata 2000), and barricades (Ilyoplax: Wada 1984); and some are related to environmental regulation, e.g., hoods (Uca: Powers and Cole 1976), chimneys (Uca: Crane 1975: 524, Thurman 1984), and igloos (Dotilla: Takeda et al. 1996). Crane (1975) reviewed these structures in fiddler crabs of the world, and chimneys were found in some subgenera: Deltuca (U. dussumieri, U. arcuata, U. forcipata, U. coarctata, and U. urvillei), Thalassuca (U. tetragonon), Amphiuca (U. chlorophthalmus), Boboruca (U. thayeri), Minuca (U. vocator), and Celuca (U. cumulanta and U. stenodactylus). Other fiddler species were also reported to build chimneys, e.g., U. elegans of the subgenus Australuca (George and Jones 1982) and U. subcylindrica of the subgenus Minuca (Thurman 1984) (reviewed in Table 1). Uca formosensis Rathbun, 1921 is a species of fiddler crab endemic to Taiwan. This species is poorly known except for its morphological characChimney Building by Male Uca formosensis Rathbun, 1921 (Crustacea: Decapoda: Ocypodidae) after Pairing: A New Hypothesis for Chimney Function