Sex-dependent energetic cost of a protandric simultaneous hermaphroditic shrimp Lysmata wurdemanni under different social conditions

We tested a hypothesis (sex-dependent energetic cost) in a protandric simultaneous hermaphroditic (PSH) shrimp Lysmata wurdemanni under different social conditions to explain the adaptive value of PSH. Two components (sex-dependent energetic cost and resource holding power) of the hypothesis were tested. Growth reduction was used to represent the energetic cost in reproduction. This study demonstrated that energetic cost of reproduction of the shrimp is generally sex-dependent, but they are strongly affected by the social environment. When male phase (MP) or euhermaphridite phase (EP) shrimp were housed individually (i.e. without social and reproductive behavior), reproductive cost (energy for gametic production only) of MP shrimp was significantly lower than that of EP shrimp (with both male and female functions). However, growth of MP shrimp did not differ from that of EP individuals when they were housed with EP shrimp, i.e. when costs of both social and mating behavior were considered. When a MP shrimp copulated with EP shrimp more than once within a molt cycle, growth was significantly reduced. Result also indicated that resource holding power of L. wurdemanni was not associated with energy burden of female function. Our results do not support the hypothesis of size-dependent energetic cost in L. wurdemanni.