Effects of prey densities and dietary supplementation on the larval development of the blue crab Callinectes sapidus Rathbun, 1896 (Brachyura: Portunidae)

Variation in larval development related to duration and number of stages is common among arthropods. This variation appears to be influenced largely by environmental factors such as prey availability and temperature, but the primary causes are poorly understood. We examined the effects of prey density and the use of polyhydroxybutyrate (PHB), an energy-storage compound, on larval duration and survival during the early development of the blue crab, Callinectes sapidus (Rathbun, 1896), using hatchery-raised animals at constant temperature (21-23 degrees C). We also determined the daily food consumption by zoeae and the number of zoeal stages that are required to reach the final megalopa stage. Newly-hatched zoeae of C. sapidus were reared until megalopae in 24-well plates under high and low prey density with and without PHB supplementation (50 and 100 mg/l). Food consumption only was significantly different when a high density of Artemia, used as food, during later development. The zoeae raised under a high prey density had a shorter duration by having fewer zoeal stages and greater survival rate than those with a low prey density. PHB supplementation, with a combination of a high prey density, increased the incidences of stage skipping without changing the duration of zoeal development. Prey density, possibly affecting the nutritional status of larvae, is a critical factor that influences the zoeal development of C. sapidus.