SPECIFIC DYNAMIC ACTION AND THE METABOLISM OF THE BRACHYURAN LAND CRABS OCYPODE-QUADRATA (FABRICIUS, 1787), GONIOPSIS-CRUENTATA (LATREILLE,1803) AND CARDISOMA-GUANHUMI LATREILLE, 1825

Oxygen uptake (MO2) was measured in the terrestrial crabs Ocypode quad rata (Fabricius, 1787), Goniopsis cruentata (Latreille, 1803) and Card isoma guanhumi Latreille, 1825 as a function of digestive state to det ermine the magnitude and time course of specific dynamic action (SDA). Following 5 days of feeding ad libitum on fish flesh, ''steady-state' ' MO2 was about 2.8, 1.0 and 1.6 mum.g-1.h-1 in Ocypode (29-31-degrees -C), Goniopsis (23-25-degrees-C) and Cardisoma (29-31-degrees-C), resp ectively. After 5 days of fasting, ''steady-state'' MO2 was decreased greatly to 1.0 and 0.5 mum.g-1.h-1 in Ocypode and Cardisoma, respectiv ely, but was not significantly changed from feeding values in Goniopsi s. Time-course experiments indicated that the peak in MO2 following a single large meal occurred within 8 h in both Ocypode and Cardisoma. T he apparent SDA persisted for longer than 50 h in Cardisoma, but less than 42 h in Ocypode. These data show that an apparent SDA of large ma gnitude and variable time course can occur in land crabs. However, the absence of any apparent SDA effect in Goniopsis indicates that it is not a necessary accompaniment to feeding in all terrestrial brachyuran s, and must be verified on a species-by-species basis.