A gas-chromatographic micromethod for respiration studies on insects.

Respiration studies on insects are usually carried out by adapting direct or indirect standard manometric techniques (Umbreit, Burris & Stauffer, 1964). An alternative method, based on the use of an electrolytic respirometer, has been occasionally used (Hebrant, 1970). The respiration of Tenebrioides mauritanicus, a stored product beetle, has been monitored at reduced pressures by the use of a complex gas chromatographic technique (Dumas, Buckland & Monro, 1969). The limitations implicit in methods hitherto serving for respiration studies relate to the number of determinations which can be conveniently carried out in reasonable periods, to sensitivity when working on individual small insects, and to difficulties encountered in measuring respiration of very active insects. The purpose of this present paper is to describe a comparatively simple and rapid micromethod for the simultaneous determination of oxygen consumption and carbon dioxide release by a gas-chromatographic technique. This method was elaborated by us in order to determine the respiratory quotient of numerous individual adult coccinellid beetles. It is particularly applicable in cases where many routine determinations of this sort are required in a limited amount of time.