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The European paper wasp, Polistes dominulus Christ, is an abundant wasp species in South and Central Europe which dispersed to the north in recent times. Polistes dominulus exhibits an energy-extensive mode of life, spending much time resting at the nest, which should be reflected in adaptations regarding gas exchange and standard metabolism. We analysed the resting metabolism (CO emission) of Polistes dominulus workers in the ambient temperature range an individual may be exposed to during a breeding season ( T = 2.4-40.6 °C) via flow through respirometry. Behaviour and endothermic activity were assessed by infrared thermography. With rising T, CO release followed an exponential increase from 27 to 149 and 802 nl g min at T = 3, 20 and 35 °C, respectively. Measurements of the thermal regime at the nest showed that resting P. dominulus are most of the time in the lower range of their standard metabolic curve. A comparison with a 'highly energetic' wasp like Vespula sp. revealed that Polistes dominulus not only optimises behaviour but also reduces metabolism to save energy. The CO emission patterns changed with ambient temperature, from discontinuous (≤25 °C) to cyclic (25-36 °C) and continuous gas exchange at higher temperatures. A pronounced break appeared in the data progression regarding cycle frequency and CO emission per gas exchange cycle between 15 and 10 °C. This striking change in gas exchange features indicates a physiological adaptation to special respiratory requirements at low temperatures. [ABSTRACT FROM AUTHOR]

The Western honeybees Apis mellifera carnica and A. m. ligustica are 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 the A. m. ligustica population only at a high temperature ( T ~ 40 °C; dVCO = 12 nl s; P < 0.05), probably due to a higher body temperature (dT = 1.5 °C; P < 0.01). The critical thermal maximum of activity and respiration was similar (difference activity CT = 0.8 °C, respiratory CT = 1.1 °C). The lethal temperature (LT) 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. [ABSTRACT FROM AUTHOR]

Abstract: Vespine wasps are known for their high endothermic capacity. Endothermic activity is directly linked to respiration. However, knowledge on wasp respiration is sparse and almost nothing is known about their resting metabolism. We investigated the yellowjackets’ CO2 production in a flow-through respirometer chamber overnight. Endothermic and behavioral activity was observed by real-time infrared thermography. Most resting wasps were ectothermic or only slightly endothermic (thoracic temperature excess against abdomen <0.6°C). In the investigated temperature range (T a =2.9–42.4°C) mean CO2 production rate of resting wasps increased steeply according to an exponential function, from 5.658μlg−1 min−1 at 8.3°C to 8.504μlg−1 min−1 at 20.2°C, 58.686μlg−1 min−1 at 35.3°C and 102.84μlg−1 min−1 at 40°C. The wasps’ respiratory critical thermal maximum (CTmax), marking the upper edge of their viable temperature range, was 45.3°C. The respiratory CTmax did not differ significantly from the activity CTmax of 44.9°C. CTmax values were considerably below that of honeybees (48.9 and 49.0°C for respiration and activity, respectively). This allows honeybees to kill wasps by heat-balling. Comparison with other arthropods showed that vespine wasps are among the insects with the highest mass-specific resting metabolic rate and the steepest increase of metabolism with ambient temperature. [Copyright &y& Elsevier]