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We investigated the respiration patterns of wasps (Vespula sp.) in their viable temperature range (2.9–42.4°C) by measuring CO2 production and locomotor and endothermic activity. Wasps showed cycles of an interburst–burst type at low ambient temperatures (T a <5°C) or typical discontinuous gas exchange patterns with closed, flutter and open phases. At high T a of >31°C, CO2 emission became cyclic. With rising T a they enhanced CO2-emission primarily by an exponential increase in respiration frequency, from 2.6mHz at 4.7°C to 74mHz at 39.7°C. In the same range of T a CO2 release per cycle decreased from 38.9 to 26.4μlg−1 cycle−1. A comparison of wasps with other insects showed that they are among the insects with a low respiratory frequency at a given resting metabolic rate (RMR), and a relatively flat increase of respiratory frequency with RMR. CO2 emission was always accompanied by abdominal respiration movements in all open phases and in 71.4% of the flutter phases, often accompanied by body movements. Results suggest that resting wasps gain their highly efficient gas exchange to a considerable extent via the length and type of respiration movements. [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]

Climate change is expected to produce shifts in species distributions as well as behavioural and physiological adaptations to find suitable conditions or to cope with the altered environment. The paper wasps Polistes dominula and Polistes gallicus are closely related species, native in the European Mediterranean region and North Africa. P. dominula has expanded its range to the relatively cooler climates of Northern and Eastern Europe, but P. gallicus remained in its original distribution area. In order to reveal their metabolic adaptation to the current climate conditions, and the impact on energy demand at future climate conditions, we investigated the respiratory metabolic rate (CO 2 production) of P. dominula from Austria and P. gallicus from Italy. In contrast to the metabolic cold adaptation hypothesis their standard metabolic rate was nearly the same and increased in a typical exponential course with increasing ambient temperature. The metabolic rate of active wasps was higher than the standard metabolic rate and increased with the wasps' activity. There was no obvious difference in the active metabolism between the two species, with the exception that some P. gallicus individuals showed some extraordinary high values. A simultaneous measurement of metabolic rate and body temperature revealed that increased CO 2 production was accompanied by endothermic activity. The two investigated populations of paper wasps are quite similar in their metabolic response to temperature, although they live in different climate regions. The spread of P. dominula into cooler regions did not have significant influence on their active and standard metabolic rate. Unlabelled Image • A comparison of the standard and active metabolic rate of Polistes dominula and P. gallicus from different climates revealed similarities. • The metabolic rate was nearly the same in both species. • Simultaneous measurement of metabolism and body temperature revealed that increased CO 2 production is accompanied by endothermic activity. [ABSTRACT FROM AUTHOR]