The circadian rhythm of the mean respiratory rates (VO2) was determined on isolated workers of Tetragonisca angustula fiebrigi (Schwarz, 1938), T. a. angustula (Latreille, 1807) and Trigona spinipes (Fabricius, 1793) in normal cycle (day/light and night/dark) conditions, during springtime. Oxygen consumption was determined at 30ºC by using a Warburg respirometer. The statistical analysis of the results revealed significant interactions among time intervals and between the species. Breathing rates were compared using the Tukey's test. A clear circadian pattern of the metabolic rhythm was observed for both species. It showed a larger consumption of oxygen during the day, with a peak between 10:00 and 15:00. At night the consumption decreased, reaching the minimum levels between 2:00 and 3:00. Tetragonisca angustula angustula and T. a. fiebrigi did not show significant differences between them but they did differed from T. spinipes, which showed larger respiratory rates.
Oxygen consumption; respiratory metabolism; stingless bees
