Different types of external gas exchange found in pupae of greater wax moth Galleria mellonella (Lepidoptera: Pyralidae)

Abstract

In outdoor and laboratory pupal populations of Galleria mellonella four types of external gas exchange were found: (i) a cyclic and sudden deep-air suction-intake, followed instantly by a rapid release of CO2, occurring at every 8-14 s at 30°C and identified as UDFµC (Unidirectional Flow Microcycles); (ii) intermittent but slow emission of CO2 without sudden air suction-intake; (iii) chaotic rhythm of gas exchange and (iv) continuous respiration.Wandering larvae at rest and mobile prepupae in cocoons exhibited the same type of gas exchange and some individual breathing patterns which persisted during later pupal development.Regular stereotyped abdominal movements acted as ventilating movements only in individuals which did not exhibit UDFµC in gas exchange. Externally imperceptible abdominal movements due to extracardiacal pulsations of haemolymphal pressure played an inessential role in active tracheal ventilation. The rhythms of abdominal movements persisted in pupae independently of the gaseous exchange type and individual breathing patterns.Among pupae taken from beehives, individuals with UDFµC dominated, while in some laboratory generations only those with chaotic breathing rhythms were found. However, no distinct developmental factors were revealed that could exert influence on the individual formation of the gas exchange pattern.