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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]

Heteroptera, or true bugs populate many climate zones, coping with different environmental conditions. The aim of this study was the evaluation of their thermal limits and derived traits, as well as climatological parameters which might influence their distribution. We assessed the thermal limits (critical thermal maxima, CTmax, and minima, CTmin) of eight seed bug species (Lygaeidae, Pyrrhocoridae) distributed over four Köppen–Geiger climate classification types (KCC), approximately 6° of latitude, and four European countries (Austria, Italy, Croatia, Bulgaria). In test tubes, a temperature ramp was driven down to −5 °C for CTmin and up to 50 °C for CTmax (0.25 °C/min) until the bugs' voluntary, coordinated movement stopped. In contrast to CTmin, CTmax depended significantly on KCC, species, and body mass. CTmax showed high correlation with bioclimatic parameters such as annual mean temperature and mean maximum temperature of warmest month (BIO5), as well as three parameters representing temperature variability. CTmin correlated with mean annual temperature, mean minimum temperature of coldest month (BIO6), and two parameters representing variability. Although the derived trait cold tolerance (TC = BIO6 − CTmin) depended on several bioclimatic variables, heat tolerance (TH = CTmax − BIO5) showed no correlation. Seed bugs seem to have potential for further range shifts in the face of global warming. [ABSTRACT FROM AUTHOR]