Metabolism and upper thermal limits ofApis mellifera carnicaandA. m. ligustica.
The Western honeybeesApis mellifera carnicaandA. m. ligusticaare closely related subspecies living in neighbouring regions. Metabolism and the upper lethal thermal limits are crucial physiological traits, adapted in the evolutionary process to environment and climate conditions. We investigated whether samples from these two ecotypes differ in these traits. The standard metabolic rate was higher in theA. m. ligusticapopulation only at a high temperature (Ta~40 °C; dVCO2=12 nl s-1;P<0.05), probably due to a higher body temperature (dTthorax=1.5 °C;P<0.01). The critical thermal maximum of activity and respiration was similar (difference activity CTmax=0.8 °C, respiratory CTmax=1.1 °C). The lethal temperature (LT50,8h) revealed higher tolerance and survival rates of the Ligustica bees (Carnica 50.3 °C; Ligustica 51.7 °C;P<0.02). Results reveal the adaptation of the two subspecies to their historic climate conditions, possibly favouring Ligustica in a warming environment.
Institut für Zoologie, Universität Graz, Universitätsplatz 2, 8010, Graz, Austria.
Helmut
H
Kovac
Institut für Zoologie, Universität Graz, Universitätsplatz 2, 8010, Graz, Austria.
Helmut
H
Käfer
Institut für Zoologie, Universität Graz, Universitätsplatz 2, 8010, Graz, Austria.
Anton
A
Stabentheiner
CRA-Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Unità di ricerca di apicoltura e bachicoltura, Via di Saliceto, 80, 42100, Bologna, Italy.
Cecilia
C
Costa
carnica; honeybee races; lethal temperature; ligustica; metabolic rate; respiration