THE PHILIPPINE 



Journal of Science 



D. General Biology, Ethnology 

 AND Anthropology 



Vol. VII JUNE, 1912 No. 3 



THE HABITS OF FIDDLER -CRABS. 



By A. S. Peaese.' 

 (From the Zoological Laboratory, University of the Philippines.) 



The habits of fiddler-crabs are of particular interest to natural- 

 ists. Since the time of Darwin ('74), these crustaceans have 

 been believed to furnish evidence of sexual selection on account 

 of the bright coloration and enormous chela of the male; these 

 characteristics contrasting strongly with the comparatively dull 

 dress and the small bilaterally symmetrical chelipeds of the 

 female. Alcock ('92, '00, '02) is convinced that ('00, p. 351) — 



In one species, at any rate (Gelasimus annulipes), the males, which are 

 greatly in excess of the females, use the big and beautifully colored cheliped 

 not only for fighting with each other, but also for "calling" the females. 



According to the same writer ('92), Milne-Edwards described 

 a South American species in which the male and female lived 

 together in a single burrow, the former closing the mouth of 

 the burrow with his large chela. But Smith and Weldon are 

 apparently not convinced that the purpose of the peculiar adap- 

 tations of male fiddlers has been demonstrated, for they say 

 ('09) — 



Though the genus Gelasimus is remarkable for the large size of one of 

 its chelae the purpose of this peculiar adaptation is unknown in the various 

 species. 



They state that the chela is believed by various writers to 

 be used for closing the burrow, as a weapon in combats, and as 

 a means of attracting the female, but do not affirm that any of 

 these uses have been demonstrated. 



^ Recently assistant professor of zoology. University of the Philippines. 

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