Evidence from mosquitoes suggests that cyclic gas exchange and discontinuous gas exchange are two manifestations of a single respiratory pattern

Abstract

In this paper we demonstrate that the apparent pattern of gas exchange in insects, as observed using flow-through respirometry, is strongly affected by the rate of flow of air through the system. This is true not only because of the time constant of the respiratory chamber in which the insect resides, but also due to the effect of flow rate on the residence time of air as it passes through the detection chamber in the gas analyzer. It is demonstrated that insects respiring with a discontinuous gas exchange pattern can appear to be using a cyclic respiratory pattern. The effects of flow rate on the respiratory pattern discerned are illustrated using the mosquito Culiseta inornata. It is demonstrated that these mosquitoes respire discontinuously. They are among the smallest insects to date in which the discontinuous gas exchange cycle has been observed.