Discontinuous ventilation in the rhinoceros beetle Oryctes Nasicornis: Direct and indirect calorimetry

Abstract

Discontinuous gas exchange cycles (DGCs) are frequently observed with insects, i.e. oxygen take up and carbon dioxide release occur interrupted by periods of a few minutes up to many hours. The paper presents direct and indirect calorimetric experiments on DGCs of the scarabid rhinoceros beetle Oryctes nasicornis. A direct/indirect calorimetric experiment is presented. Total and specific heat production rates amount to 0.56mWand 0.42mWg –1 in the first period without DGCs and to 0.43 mW (0.32 mW g –1 ) in the second phase, resp. The mean DGC amplitude is 0.184 mW and thus between 33 and 66% of the total turnover.