Resistance to starvation of first-stage juveniles of the Caribbean spiny lobster

Abstract

The non-feeding postlarva (puerulus) of spiny lobsters actively swims from the openocean to the coastal habitats where it settles and molts to the first-stage juvenile (JI).Because pueruli use much of their energy reserves swimming and preparing for thepost-settlement molt, the survival of JIs presumably depends on resuming feedingas soon as possible. To test this hypothesis, the resistance to starvation of JIs of theCaribbean spiny lobster, Panulirus argus, was evaluated by measuring their pointof-no-return (PNR, minimum time of initial starvation preventing recovery afterlater feeding) and point-of-reserve-saturation (PRS, minimum time of initial feedingallowing for food-independent development through the rest of the molting cycle) ina warm and a cold season. Each experiment consisted of eight groups: a continuouslyfed control (FC) group, a continuously starved control (SC) group, and six groupssubjected to differential periods of either initial starvation and subsequent feeding (PNRexperiments) or initial feeding and subsequent starvation (PSR experiments). No JIsmolted under continuous absence of food (SC). In both PNR experiments (temperaturein warm season: 29.79±0.07 °C, mean±95% CI; in cold season: 25.63±0.12 °C)mortality increased sharply after 9 d of initial starvation and intermolt periods increasedwith period of initial starvation, but were longer in the cold season. The PNR50 waslonger in the warm season (12.1±1.2 d, mean±95% CI) than in the cold season(9.5±2.1 d). In PRS experiments (temperature in warm season: 29.54±0.07 °C; in coldseason: 26.20±0.12 °C), JIs that molted did so near the end of the feeding period; all JIsinitially fed for up to 6 d succumbed, and no JIs molted after 13 d of starvation despitehaving fed previously. The PRS50 did not differ between the cold (13.1±0.7 d) andwarm seasons (12.1±1.1 d). JIs of P. argus exhibit a remarkable resistance to starvationconsidering that the previous non-feeding, energy-demanding puerulus phase lasts for∼3 weeks. However, JIs appear to have a relatively higher degree of dependence on foodto complete development to JII during the cold season than during the warm season.Therefore, JIs of P. argus would appear to be more resistant to starvation during thewarm season.