Temperature, not net primary productivity, drives continental-scale variation in insect flight activity

Area of Science:

• Ecology
• Macroecology
• Climate Change Biology

Background:

• Energy availability influences ecosystem-wide abundance patterns.
• Temperature and net primary productivity are key environmental factors potentially driving insect abundance.

Purpose of the Study:

• To investigate the roles of temperature and net primary productivity in shaping continental-scale flying insect abundance.
• To utilize weather surveillance radar data for a novel assessment of insect flight activity.

Main Methods:

• Employed data from the United States NEXRAD weather radar network to create a near-daily dataset of insect flight activity.
• Analyzed insect flight activity across gradients of temperature and net primary productivity.
• Examined biome-specific variations in the temperature-abundance relationship, considering water availability.

Main Results:

• Insect flight activity showed a positive correlation with mean annual temperature, explaining 38% of variation across sites.
• Net primary productivity did not explain significant additional variation in insect abundance.
• Significant differences in insect flight activity were observed across biomes, with highest abundance in temperate and subtropical grasslands.

Conclusions:

• Temperature significantly constrains insect metabolism, development, and flight activity, shaping macroecological patterns of ectotherm abundance.
• Water availability mediates the temperature-abundance relationship in arid-xeric shrublands and forests.
• Findings are vital for predicting insect community dynamics under future warming scenarios and contribute to global insect biodiversity monitoring efforts.