Metadata are provided in each data sheet. Links to a Shiny app of an interactive simulation, and the underlying R script (on GitHub) are provided below. Refer to manuscript for full details.
Abstract 1. Conserving energy through winter is important for the fitness of temperate insects. While insects can use buffered microhabitats, metabolic suppression, or decreases in the thermal sensitivity of metabolic rate to override seasonal-scale thermal trends, the relative importance of these strategies for limiting energy use by insects overwintering in soil remains largely underexplored. 2. We used a combined laboratory, field, and simulation approach to investigate the overwintering energetics of the western bean cutworm (Striacosta albicosta), a univoltine lepidopteran pest of dry beans and corn that overwinters underground as a dormant prepupa. 3. We hypothesized that (1) the selection of thermally-buffered microhabitats (i.e. deeper soil sites) reduces energy use in early autumn and late spring, and that (2) changes in the metabolic rate-temperature relationship reduce the impact of elevated temperatures on overwintering energy use. 4. We provide evidence that during the warmest parts of winter, dormant S. albicosta prepupae that had burrowed deep benefited from a cool, stable microclimate, whereas those near the soil surface appeared to rely on deeper metabolic suppression to maintain their energy stores. 5. Although elevated temperatures in the laboratory depleted their energy reserves, these strategies appear sufficient to limit energy drain under natural conditions in the field. 6. We suggest that small-scale variation in the depth of soil refuges may mediate the interaction between the risk of energy drain and changes in the metabolic rate-temperature relationship in soil-overwintering insects.

Metadata are provided in each data sheet. Links to a Shiny app of an interactive simulation, and the underlying R script (on GitHub) are provided below. Refer to manuscript for full details.
Abstract 1. Conserving energy through winter is important for the fitness of temperate insects. While insects can use buffered microhabitats, metabolic suppression, or decreases in the thermal sensitivity of metabolic rate to override seasonal-scale thermal trends, the relative importance of these strategies for limiting energy use by insects overwintering in soil remains largely underexplored. 2. We used a combined laboratory, field, and simulation approach to investigate the overwintering energetics of the western bean cutworm (Striacosta albicosta), a univoltine lepidopteran pest of dry beans and corn that overwinters underground as a dormant prepupa. 3. We hypothesized that (1) the selection of thermally-buffered microhabitats (i.e. deeper soil sites) reduces energy use in early autumn and late spring, and that (2) changes in the metabolic rate-temperature relationship reduce the impact of elevated temperatures on overwintering energy use. 4. We provide evidence that during the warmest parts of winter, dormant S. albicosta prepupae that had burrowed deep benefited from a cool, stable microclimate, whereas those near the soil surface appeared to rely on deeper metabolic suppression to maintain their energy stores. 5. Although elevated temperatures in the laboratory depleted their energy reserves, these strategies appear sufficient to limit energy drain under natural conditions in the field. 6. We suggest that small-scale variation in the depth of soil refuges may mediate the interaction between the risk of energy drain and changes in the metabolic rate-temperature relationship in soil-overwintering insects.

Low winter temperatures in temperate climates can limit the success of non-native species. The Asian longhorned beetle, Anoplophora glabripennis, is an invasive wood-boring pest of hardwood trees in North America and Europe. Native A. glabripennis populations are spread across several climate zones in China and the Korean Peninsula and are likely to encounter low temperatures in at least some of this range. Understanding the lethal limits of the overwintering life stages of A. glabripennis is essential for accurately modeling the risk that invasive populations pose to non-native environments. In this study, we provide the first systematic characterization of the cold tolerance strategy and lower lethal limits of A. glabripennis eggs, larvae, and pupae. In diapausing larvae, the most common overwintering stage in this species, we measure hemolymph glycerol and osmolality and identify the effects of prolonged low temperature exposure. In developing pupae, we identify sublethal effects caused by low temperature exposure before freezing. Eggs and larvae were the most cold-tolerant life stages; eggs were freeze-avoidant with an average supercooling point of -25.8 °C and larvae were freeze tolerant with an LT90 of -25 °C. Hemolymph osmolality of freeze-tolerant larvae, on average, increased to 811 mOsm during chilling. This increase was primarily driven by a concurrent, average increase of 232 mM hemolymph glycerol. Pupae died upon exposure to freezing temperatures, but accumulate strong sublethal effects prior to freezing, indicating that they are chill susceptible. Taken together, these data will be useful to inform species distribution modeling in A. glabripennis.

Variable, changing, climates may affect each participant in a biotic interaction differently. We explored the effects of temperature and plasticity on the outcome of a host-pathogen interaction to try to predict the outcomes of infection under fluctuating temperatures. We infected Gryllus veletis crickets with the entomopathogenic fungus Metarhizium brunneum under constant (6 °C, 12 °C, 18 °C or 25 °C) or fluctuating temperatures (6 °C to 18 °C or 6 °C to 25 °C). We also acclimated crickets and fungi to constant or fluctuating conditions. Crickets acclimated to fluctuating conditions survived best under constant conditions if paired with warm-acclimated fungus. Overall, matches and mismatches in thermal performance, driven by acclimation, determined host survival. Mismatched performance also determined differences in survival under different fluctuating thermal regimes: crickets survived best when fluctuating temperatures favoured their performance (6 °C to 25 °C), compared to fluctuations that favoured fungus performance (6 °C to 18 °C). Thus, we could predict the outcome of infection under fluctuating temperatures by averaging relative host-pathogen performance under constant temperatures, suggesting that it may be possible to predict responses to fluctuating temperatures for at least some biotic interactions.

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