Level of ecdysteroids in the hemolymph of the freshwater prawn, Macrobrachium rosenbergii (Crustacea: Decapoda) in relation to the phenomenon of cheliped autotomy in males

Ecdysteroid titers were determined in the hemolymph of adult freshwater prawn, Macrobrachium rosenbergii, during various stages of the molt cycle, using radioimmunoassay. A comparison was made between hormone levels in males which undergo normal molt and dominant males of the population which periodically commit cheliped autotomy. The latter is a recently discovered phenomenon whereby a male voluntarily sheds off both its long claws at molt, once the ratio between body length and combined claw length reaches a ceiling level of about 1:3. Shortly before an autotomizing molt, hormone levels were about three times higher than on the eve of a normal molt.