Diurnal rhythm in levels of haemolymph sugar and hyperglycaemic activity of eyestalk extract in the fresh water rice field crab (Oziotelphusa senex senex Fabricius).

The concentration of haemolymph sugar and the hyperglycaemic activity of eyestalk extract was measured six times (8, 12, 16, 20 and 4 h) over a 24-h period. The concentration of haemolymph sugar and hyperglycaemic activity of eyestalk extract was higher during the night (0 h through 8 h) than that noted in day time (12 h). The variations are closely related to the activity of the animal.