BEHAVIOUR 03 



42), and often coloured in contrast with the rest of the hody. Two 

 typical examples of brilliant male coloration are U. batuenta and 

 U. beebi: the former has a white-speckled, golden-brown carapace 

 and the chela is pure white, dazzling and polished, the latter has 

 the front part of the carapace brilliant iridescent green, part $f the 

 large limb is bright ochre or rosy pink and the fingers of the chela 

 are white. These descriptions apply to displaying males, when 

 otherwise engaged they are not so bright. 



The display is usually directed towards a female near at hand, 

 and consists of waving the large chela in a manner which is 



Fig. 42. Male of Uca pugilator. 



characteristic for each species. Uca batuenta raps its chela smartly 

 three or four times on the ground; U. oerstedi stretches its chela out- 

 wards and upwards, and while it is fully extended the front legs are 

 vibrated rapidly, displaying brilliant blue patches. 



The males may spend many hours displaying to females which 

 show no reaction to their antics, but eventually a female will follow 

 a displaying male into its burrow or mate with it on the surface of 

 the sand. There is no evidence of sexual selection in the sense of a 

 female choosing the brightest or most active male, but the character- 



