Heartbeat and body movement: roles in gas exchange in Galleria mellonella L. (Lepidoptera: Pyralidae) pupae

The objective of the present article is to analyse the role of heartbeat and body movements in respiratory function in Galleria mellonella L. (Lepidoptera: Pyralidae) pupae with clear gas exchange cycles. We did not find any direct evidence of co-ordination between heartbeat and respiration or body movements and respiration. Cyclic CO₂ output was independent of abdominal movements and heart pulsations during the entire pupal development. In young pupae, heart activity periods were independent of abdominal movements. In middle-aged pupae, there appeared a clear trend towards the coincidence of heartbeat periods with the periods of abdominal movements. In late pupae, the heart pulses and the contractions of body skeletal muscles were mostly synchronized. It may be suggested that the contractions of intersegmental somatic abdominal muscles support the heartbeat, and, in this way, the hemolymph flow is accelerated. The heart and circulatory action may facilitate gaseous diffusion in the tracheae.