EFFECTS OF SALINITY AND STARVATION ON LARVAL DEVELOPMENT OF THE CRABSARMASES-RICORDI AND ARMASES-ROBERTI (DECAPODA, GRAPSIDAE) FROM JAMAICA, WITH NOTES ON THE BIOLOGY AND ECOLOGY OF ADULTS

Adult ecology, egg production, larval development, salinity tolerance, and starvation resistance of the grapsid crabs Armases ricordi and A. roberti were studied in Jamaica. The species have different adult hab itats. Armases ricordi lives in dry hot habitats up to 200 m from the shore, whereas A. roberti lives on the banks of fresh-water rivers up to 9.6 km from the sea, a relatively moist habitat with moderate tempe rature variations. Newly deposited eggs were significantly larger in A . roberti (0.40 mm) than in A. ricordi (0.35 mm). Both species produce d many eggs per clutch, more than one clutch in an intermolt stage, an d at least one clutch of eggs was fertilized without remating. Ovigero us females of A. ricordi migrate to the sea fur larval release, wherea s A. roberti apparently release the larvae into the river to be transp orted to the sea. In both species, larval development takes place in t he sea and consists of 4 zoeal stages. Duration of larval development did not differ between A. ricordi (16.1 days) and A. roberti (16.9 day s!, but the megalopa stage in A. roberti (12.0 days) was longer than i n A. ricordi (9.1 days). In both species, larvae depended on food inta ke in order to complete development, and the duration of survival in s tarved larvae varied significantly between hatches. Larvae of Armases roberti, hatched with a larger body size, showed a higher endotrophic potential and the first crab stage was larger than in A. ricordi. The range of salinity tolerated for development to the megalopa was 20-45 ppt in A. ricordi and 15-45 ppt in A. roberti. The species differed gr eatly in salinity tolerance in the first zoeal stage, with 100% of the larvae surviving fresh water only for 1 h in A ricordi, but for 2.5 d ays in A. roberti, allowing the first zoea of the latter to be transpo rted to the sea from distant inland hal,habitats. The differences betw een A. roberti and A. ricordi in endotrophic potential, body size, and fresh-water tolerance of the first zoea are likely to be related to t he larger egg size and, hence, larger yolk provisioning per egg in A. roberti. We discuss the significance of migration and larval release p attern in relation to inland distribution of adults for species with m arine planktonic development.