Spermatogenesis and Sperm Storage in the Testes of the Behaviorally Distinctive Male Morphotypes ofMacrobrachium rosenbergii(Decapoda, Palaemonidae)

Abstract

Adult males of the freshwater prawn Macrobrachium rosenbergii differentiate into three morphotypes. Each morphotype develops in sequence in the adult male population from small males through orange claw males to dominant blue claw males. Small males and blue claw males are sexually active, while orange claw males represent a sexually inactive intermediate stage engaged in somatic growth.To further examine these behavioral characteristics on a physiological level, testes from each of the morpho types were cultured in vitro. The rate of [3H]-thymidine incorporation, representing DNA synthesis, and the amount of sperm released into the culture media were recorded. In parallel, the relative wet weight of testes from the different morphotypes were recorded and histological preparations were examined.The relative weight of the testes from small males was significantly greater than in the other morphotypes. The testes of small males were both active in spermatogenesis and contained a large amount of mature sperm...