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Simple Summary: Ambient temperature is a main external parameter in the life of ectothermic insects. It affects egg and larval development as well as adults' survival, thriving and propagation, and successful overwintering. We conducted temperature measurements in Central Europe in the habitat and in the microhabitats of Pyrrhocoris apterus, a herbivorous bug species almost ubiquitous in Eurasia, with a high invasive potential (USA, Central America, India and Australia). and set them against freely available climate data commonly used to characterize habitat climate. Our temperature measurements were also compared to the bug species' thermal limits (critical thermal minima and maxima). Ambient temperatures outside the thermal boundaries of P. apterus can and do occur in the habitat. Microhabitat measurement showed that in summer, individuals simply moved from hot areas to cooler ones, and in winter they sought areas with bearable temperatures for hibernation. Temperatures in these particular areas are not (always) represented in large-scale climate tables, leading to possible misinterpretation of the future dispersal behavior, e.g., of invasive species. Ambient temperature is a main parameter that determines the thriving and propagation of ectothermic insects. It affects egg and larval development as well as adults' survival and successful overwintering. Pyrrhocoris apterus is a herbivorous bug species almost ubiquitous in Eurasia. Its distribution extends from the Atlantic Coast to Siberia, Northwest China and Mongolia. After introduction, it established successfully in the USA, Central America, India and Australia, which indicates a high invasive potential of this species. We determined the climatic conditions in Central Europe in a habitat where P. apterus has been continuously observed for decades. We conducted temperature measurements in the habitat and in the microhabitats where individuals could be found during the year and set them against freely available climate data commonly used to characterize habitat climate. Our temperature measurements were also compared to thermal limits (critical thermal minima and maxima). Although ambient temperatures outside the thermal boundaries of P. apterus can and do occur in the habitat, the bugs thrive and propagate. Microhabitat measurement in winter showed that individuals sought areas with favorable temperatures for hibernation. In particular, these areas are not (always) represented in large-scale climate tables, leading to possible misinterpretation of future patterns of spread of invasive species spread. [ABSTRACT FROM AUTHOR]

The metabolism of ectotherms is temperature-dependent, and the exponential nature of the metabolic rate- temperature relationship means that warmer temperatures are disproportionately affecting the energy balance. T SB a sb (standard met.) temperature deviation from microclimate ambient nest temperature was -3.6 °C in I P. dominula i , -2.4 °C in I P. gallicus i , and -3.3 °C in I P. biglumis i ). The energetic calculations were conducted using temperature-dependent metabolic rate models of the three I Polistes i species, I P. dominula i , I P. gallicus i and I P. biglumis i [[17], [29]], and adequate body temperature models [[4], [17]]. The nest ambient air temperatures in the three habitats were clearly elevated above the meteorological standard ambient temperature recorded by the nearest weather stations (temperature difference, I P. dominula i : 3.6 °C, I P. gallicus i : 2.4 °C, I P. biglumis i : 3.3 °C; Figure 2). [Extracted from the article]

Winter in climatic regions with low temperatures is a challenge for overwintering insects. They are exposed to temperature extremes, which directly cause mortality or lead to energy depletion. The winter hibernaculum of paper wasp gynes protects from predators and rain, but only poorly from ambient temperature. In order to detect physiological adaptations to differing climates, we compared the respiratory metabolism of overwintering gynes of two polistine species from the Mediterranean climate in Italy (Polistes dominula and Polistes gallicus), and of one species from the temperate climate in Austria (Polistes dominula). The wasps' CO2 emission was measured with stop‐flow respirometry in a temperature range from 2.5 to 20 °C. The mass‐specific standard (resting) metabolic rate, the main type of metabolism of the dormant insects during overwintering, increased exponentially with ambient temperature but was suppressed in comparison to individuals measured in the summer, which conserves the energy stores. In addition, it was lower in the Mediterranean species (P. dominula and P. gallicus) in comparison to the temperate species (P. dominula), especially at higher temperatures. The active metabolic rate was suppressed to a similar amount. The suppressed metabolism of the overwintering Mediterranean gynes could be an adaptation to the higher winter temperatures to prevent a premature depletion of the energy resources. [ABSTRACT FROM AUTHOR]