Different Scales, Different Rules: How Do Temperature and Radiation Across Macro- and Microclimate Shape Forest...

Area of Science:

• Ecology
• Zoology
• Climate Change Biology

Background:

• Ecophysiological rules predict varying insect body size and color relationships with thermal environments.
• Forests exhibit scale-dependent thermal conditions, influencing insect trait-environment interactions.
• Understanding these relationships is vital for predicting insect community responses to climate change.

Purpose of the Study:

• To investigate how temperature and solar radiation shape insect communities at both macro- and microclimatic scales.
• To test if different insect taxa with distinct activity periods respond differently to environmental variables.
• To evaluate the applicability of ecophysiological hypotheses across different spatial scales.

Main Methods:

• Utilized linear mixed-effect models to analyze insect community data from five German forest regions (2007-2018).
• Assessed responses of mean community traits (body size, color) to macro- and microclimatic variables.
• Focused on diurnal Coleoptera, Heteroptera, and nocturnal Lepidoptera.

Main Results:

• Smaller Coleoptera and Lepidoptera, and lighter Lepidoptera, were found with increasing seasonal temperature, supporting Heat Conservation and Thermal Melanism Hypotheses.
• Increasing solar radiation correlated with smaller, darker Coleoptera and darker Lepidoptera in open canopies, aligning with Heat Transfer Theory and Bogert's Rule.
• Heteroptera showed only body size responses at the macroclimatic scale.

Conclusions:

• Insect community responses to macroclimate differ from microclimate responses, influenced by taxon-specific life history traits.
• Scale-dependent environmental filtering shapes insect communities, with implications for climate change.
• Further research on arthropods across microclimate gradients is needed to fully understand these mechanisms.