EFFECTS OF SALINITY, TEMPERATURE, AND STARVATION ON THE LARVAL DEVELOPMENT OF ARMASES (=SESARMA) MIERSII (RATHBUN, 1897), A SEMITERRESTRIALCRAB WITH ABBREVIATED DEVELOPMENT (DECAPODA, GRAPSIDAE)

The development of the Jamaican grapsid crab Armases miersii was studi ed in laboratory experiments under various conditions of salinity, tem perature, and starvation. Females produced 908-4,334 medium-sized eggs (mean diameter = 0.51 mm). Development was abbreviated and consisted of 3 morphologically advanced zoeal stages and 1 megalopa. Development to the first crab stage took place in salinities ranging from 5-50 pp t. With increasing temperatures, duration of development decreased and survival at low salinities increased. These features enable the larva e to survive in a highly variable environment, supratidal rock pools a long the coast of Jamaica. When continuously starved, energy reserves in larvae were sufficient for development through the first and occasi onally the second zoeal stage, but later stages must feed in order to survive. Compared to other species of Armases, A. miersii produced few er, larger eggs, larval development consisted of only 3 instead of 4 z oeal stages, larvae tolerated a wider range of salinities, and showed a higher degree of lecithotrophy. The abbreviated development and part ial lecithotrophy are discussed as a step toward emanicpation from the marine environment.