LARVAL FEEDING RHYTHMS AND FOOD-CONSUMPTION BY THE RED FROG CRAB RANINA-RANINA (DECAPODA, RANINIDAE) UNDER LABORATORY CONDITIONS

Newly hatched R. ranina zoeas were held individually and fed a fixed n umber of Artemia nauplii at 25 and 29-degrees-C, to examine feeding rh ythms and the quantities consumed. During the daytime zoeas ate on ave rage 2.6 times more at 25-degrees-C and 2.8 times more at 29-degrees-C than at night, through all zoeal instars. Feeding activity during an instar was described by parabola-shaped quadratic or polynomial functi ons of days after ecdysis in later instars, although large individual variation was observed at both temperatures. Total quantities of prey consumed during each instar were expressed as exponential functions of an instar. Zoeas at 29-degrees-C ate 1.05-1.45 times as much prey dur ing each instar and 1.47-1.90 times as much daily compared with those at 25-degrees-C. The total quantities of prey consumed during a day an d during an instar were extremely high compared with other decapod spe cies. Instar VII zoeas consumed 55% of the total prey intake during th e zoeal period at 25-degrees-C and 51% at 29-degrees-C.