Active regulation of respiration and circulation in pupae of the codling moth (Cydia pomonella)

Regulation of autonomic physiological functions has been investigated by me ans of multisensor electronic methods, including electrocardiographic recor ding of heartbeat, strain-gauge recording of extracardiac hemocoelic pulsat ions (EHPs), anemometric recording of air passage through spiracles and res pirographic recording of O-2 consumption and CO2 output. Pupae of Cydia exh ibit continuous respiration without remarkable bursts of CO2. The dorsal ve ssel of these pupae exhibited regular heartbeat reversals characterized by shorter intervals of faster (forward oriented or anterograde) pulsations an d longer intervals of slower (backward oriented or retrograde) peristaltic waves. The periodically repeated EHPs were present during the whole pupal i nterecdysial period. The internal physiological mechanisms regulating the c ardiac (heartbeat) and extracardiac (EHP) pulsations were completely indepe ndent for most of the pupal instar. Simultaneous multisensor analysis revea led that the anterograde heartbeat of the dorsal vessel had similar but not identical frequency with EHPs. During advanced pharate adult development, frequency of cardiac and extracardiac pulsation periods profoundly increase d until almost uninterrupted pulsation activity towards adult eclosion. At this time, the cardiac and extracardiac pulsations occasionally performed i n concert, which enhanced considerably the efficacy of hemolymph circulatio n in pharate adults with high metabolic rates. The fastest hemolymph flow t hrough the main body cavity was always associated with EHPs and with antero grade heartbeat. Simple physical diffusion of O-2 and CO2 through spiracles (diffusion theory of insect respiration) does not play a significant role in pupal respiration. Instead, several kinds of regulated, mechanical venti lations of the tracheal system, including EHPs are responsible for effectiv e tracheal ventilation. (C) 2001 Published by Elsevier Science Ltd.