Direct calorimetric experiments on the social insects : honeybees, bumblebees and hornets are described as function of castes, age, number of animals in a group, temperature, sound generation, hibernation and influence of pheromones. Two honeybee subspecies, the European bee Apis mellifera carnica and the Egyptian bee Apis mellifera lamarckii, were compared calorimetrically in their energy metabolism which differed considerably in favour of the more alert Egyptian form. Moreover, thermoelectric cooling boxes for camping were applied as simple heat conduction calorimeters and as artificial nesting facilities for bumblebees and hornets. Their colonies could be monitored calorimetrically and thermometrically throughout the season. In spring, initial nests with only a few workers and one queen were collected in the field and transferred to these boxes where they continued their normal development up to full size of several hundred individuals. By this means, energy turnover of insect colonies could be evaluated under varying conditions.