Temperature plays a key role in the development and population maintenance of arthropods, especially for those living in cold environments. In the temperate zone, one of the most common soil-dwelling arthropods is Collembola. Instead of tracking warm and thermal temperature ranges, some Collembola species are psychrotrophic, i.e., they are well-adapted to lower temperatures. We investigated Desoria ruseki (Isotomidae), a Collembola species widely distributed in high latitudes in the Palearctic and adapted to winter, to determine the crucial temperature conditions for the sustainability of field populations of this winter-adaptive arthropod. We incubated the adult individuals of the species at six temperatures ranging from -5°C to 30°C for 98 days. We found that 0°C and 5°C, corresponding to the temperatures when the species is active in the field between late autumn (November) and early spring (April), were the best temperatures for the survival of the lab individuals. However, they died out quickly at temperatures above 20°C without laying eggs. In contrast, the species could lay eggs between 0℃ and 15℃: the higher the temperature was, the earlier they laid eggs. In addition, longer periods were needed for juveniles to hatch from eggs at lower temperatures. Our study indicates that, rather than colder conditions, hotter environments are likely to be more detrimental to the winter-adaptive Collembola species, thereby suggesting major threats to biodiversity at high latitudes under the current global warming regimes.

The adaptations of omnivorous insects to food are manifested in a multifaceted manner, and the availability of food resources directly determines insect feeding tendencies, which contribute to a complex insect-food relationship and impact insect functionality in the environment. Stable isotope analysis was applied to test the

Flower-visiting insects have co-evolved with flowering plants. While it has been shown that floral traits and environmental factors influence insect visitation during the day, it is still unclear how these factors influence their visitation at night. We sampled a montane meadow located near Jilin in northeastern China in July and August of 2019, for 4 nights each month, and two time periods each night. We sampled 94 flower-visiting insect species in total and documented floral traits and ambient factors. We first allocated all the insects to three functional groups (pollination, predation, and herbivory). Most nocturnal insects exhibited predation behavior, and had the highest species turnover rate. We then focused on environmental factors and found that ambient temperature and relative humidity strongly influenced the diversity of flower-visiting insects. In addition, variation partitioning analysis suggested that ambient temperature had a stronger effect on the flower-visiting insects during the early night hours, whereas relative humidity had a stronger effect on them in the later night hours. Finally, focusing on floral traits, most insects preferred flowers with moderately sized corolla diameters (20 to 30 mm). Furthermore, display size had a strong linear correlation with flower-visiting insect species richness and frequency of presence. In sum, our findings suggest that ambient temperature, relative humidity and floral display size strongly regulate the behavior of nocturnal flower-visiting insects.

Flower-visiting insects have co-evolved with flowering-plants. While it has been shown that floral traits and environmental factors influence insects visitations during the day, it is yet unclear how these factors influence insects visitations at night. We sampled a montane meadow located near Jilin in northeastern China in July and August in 2019, 4 nights each month, and two time periods each night. We sampled 94 flower-visiting insect species in total and documented the floral traits and ambient factors. First, focusing on the insects functions, we allocated all insects into three functional groups (pollination, predation, and feeding). We found that most nocturnal insects exhibited predation behavior, and they had the highest species turnover rate. Second, focusing on the environmental factors, we found that ambient temperature and relative humidity strongly influence the diversity of flower-visiting insects. Variation partitioning analysis further suggested that ambient temperature has a stronger effect on the flowering-visiting insects at early night, while the relative humidity has a stronger effect on the flowering-visiting insects at late night. Third, focusing on floral traits, we found that most insects have a preference for flowers with moderately-sized corolla diameters (20 to 30 mm). Furthermore, display size had a strong linear correlation with flowering-visiting insect species richness and frequency of presence. In sum, our findings suggest that ambient temperature, relative humidity, and floral display size strongly regulate nocturnal flower-visiting insects.

Temperature plays a key role in the development and population maintenance of arthropods, especially for those living in cold environments. In the temperate zone, one of the most common soil-dwelling arthropods is Collembola. Instead of tracking warm and thermal temperature ranges, some Collembola species are psychrotrophic, i.e., they are well-adapted to lower temperatures. We investigated Desoria ruseki (Isotomidae), a Collembola species widely distributed in high latitudes in the Palearctic and adapted to winter, to determine the crucial temperature conditions for the sustainability of field populations of this winter-adaptive arthropod. We incubated the adult individuals of the species at six temperatures ranging from − 5°C to 30°C for 98 days. We found that 0°C and 5°C, corresponding to the temperatures when the species is active in the field between late autumn (November) and early spring (April), were the best temperatures for the survival of the lab individuals. However, they died out quickly at temperatures above 20°C without laying eggs. In contrast, the species could lay eggs between 0℃ and 15℃: the higher the temperature was, the earlier they laid eggs. In addition, longer periods were needed for juveniles to hatch from eggs at lower temperatures. Our study indicates that, rather than colder conditions, hotter environments are likely to be more detrimental to the winter-adaptive Collembola species, thereby suggesting major threats to biodiversity at high latitudes under the current global warming regimes.