Effects of early starvation periods on zoeal development of brachyuran crabs

Larvae of the crabs Menippe mercenaria Say (Menippidae), Panopeus herbstii Milne-Edwards, Neopanope sayi Smith (Xanthidae), Sesarma cinereum Bosc (Grapsidae), and Libinia emerginata Leach (Majidae) were reared in the laboratory. Starvation periods different in length and timing within the first zoeal stage were studied as to their effects on later development and survival rate. After 1-3 days of initial feeding, most larvae had accumulated enough reserves to reach the second stage, independently of further food availability. The development of the survivors was delayed in the following stages, and their later mortality rate was higher than the fed controls. Starvation periods commencing directly after hatching of the larvae exert far stronger negative effects than those beginning later. All observations suggest a particularly sensitive phase in the beginning of larval life in brachyurans. When initial starvation periods exceed the point-of-no-return (PNR), the larvae will die later, even if feeding begins long before the energy reserves are depleted. Temporary lack of suitable prey may be an ecological factor controlling the survival of crab larvae as effectively as physical factors.