Discontinuous gas exchange cycles and active ventilation in pupae of the bumblebee Bombus terrestrisMarika Mända, Aare Kuusika, Ants-Johannes Martina, Ingrid H Williamsb, Anne Luika, Reet Karisea, Luule Metspalua and Külli Hiiesaara
a Institute of Plant Protection, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia
b Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
(Received 2 October 2003 - revised 25 June 2004 - accepted 2 March 2005; Published online: 19 October 2005)
Abstract - Discontinuous release of CO2 (bursts) or discontinuous gas exchange cycles (DGC), metabolic rate (MR) and ventilation movements were simultaneously recorded from the pupae of the bumblebee Bombus terrestris by means of an electrolytic respirometer and an infrared gas analyser (IRGA) combined with an infrared actograph (IRA). After recovering from stress, the early stage pupae showed irregular continuous respiration, mid-stage pupae displayed regular DGC. The bursts of CO2 release tended to coincide with abdominal contractions. In late stage pupae all bursts of CO2 were associated with active ventilation. During interburst periods, spikes appeared on the respirograms interpreted as micro-cycles of passive suction ventilation (PSV). After removal from their cocoons, the pupae exhibited frequent periods of muscular activity due to stress. Water loss of pupae inside cocoons was significantly less than that from pupae without cocoons.
Key words: Bombus terrestris L. / passive suction ventilation / standard metabolic rate / respirometry
Corresponding author: Marika Mänd email@example.com
© INRA, DIB-AGIB, EDP Sciences 2005