Puberty and Sexual Maturity in Male Crabs Essay

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Results of the present study show that the level of allometry of male chelae does not change abruptly at pubertal moult and therefore immature and mature crabs cannot be distinguished on this basis. This replicats the findings of Sumpton (1990b) for Charybdis natator, in which he did not find any evidence of discontinuities in the relative growth of male chelae. It is however well documented for portunid crabs that the level of allometry of male chelae does change suddenly at the pubertal moult in such species as Scylla serrata (Knuckey, 1996; Imtiaz et al., 1998), S. olivacea and S. paramamosain (Overton and Macintosh, 2002), Portunus pelagicus (Shields and Wood, 1993), P. sanguinolentus (Rasheed and Mustaquim, 2010), Liocarcinus …show more content…
It is well known that the role of abdomen, in brachyuran crabs, is quite different in the two sexes. Abdomen in male crabs is narrow and it covers and supports the first two pairs of pleopods, which are modified into intromittent organs. Abdomen in female crabs is broad and it has entirely different role. Each segment of the abdomen has a pair of hairy pleopods to which eggs attach at the time of spawning and the whole abdomen in conjunction with the sternum forms a chamber in which eggs are carried and incubated (Hartnoll, 1982). Results of the presenet study reveal that the level of allometry suddenly changes at puberty moult and then the growth of abdomen proceeds at a higher level of allometry. In between the two phase allometries, there is a transition phase, individuals of which cannot be alloted to one or other of the two phases with certainity. This finding of the present study is in agreement with some previous studies on portunid crabs. For instance, in Charybdis bimaculata puberty in female is clearly indicated by a sharp increase in the width of abdomen (Doi et al., 2008). In their study of sexual maturity for female mud crab Scylla olivacea and S. paramamosain from Thailand, Overton and Macintosh (2002) found sudden change in the level of abdominal allometry at sexual maturity. Similar results were reported by Imtiaz et al. (1998) for female Scylla serrata from Pakistan, Muino et al. (1999) for female Liocarcinus depurator from Spain,

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