Endothermic heat production in honeybee winter clusters.
In order to survive cold northern winters, honeybees crowd tightly together in a winter cluster. Present models of winter cluster thermoregulation consider the insulation by the tightly packed mantle bees as the decisive factor for survival at low temperatures, mostly ignoring the possibility of endothermic heat production. We provide here direct evidence of endothermic heat production by 'shivering' thermogenesis. The abundance of endothermic bees is highest in the core and decreases towards the surface. This shows that core bees play an active role in thermal control of winter clusters. We conclude that regulation of both the insulation by the mantle bees and endothermic heat production by the inner bees is necessary to achieve thermal stability in a winter cluster.
Stabentheiner
Anton
A
Institut für Zoologie, Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria. anton.stabentheiner@uni-graz.at
Pressl
Helga
H
Papst
Thomas
T
Hrassnigg
Norbert
N
Crailsheim
Karl
K
D000064:Acclimatization / Q000502:physiology; D000818:Animals; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D003081:Cold Climate; D012621:Seasons; D012768:Shivering / Q000502:physiology; D022722:Thermogenesis / Q000502:physiology*