Insect communities under skyglow: diffuse night-time illuminance induces spatio-temporal shifts in movement and...

Area of Science:

• Ecology
• Environmental Science
• Behavioral Ecology

Background:

• Artificial light at night (ALAN) poses risks to ecosystems by affecting physiology, behavior, and species interactions.
• Movement and predation are key ecological processes potentially sensitive to ALAN, especially in nocturnal invertebrates.
• Limited research exists on ALAN's community-level impacts on these fundamental ecological processes.

Purpose of the Study:

• To investigate how varying intensities of artificial light at night (ALAN) affect insect movement and predation rates within a community context.
• To quantify the spatio-temporal responses of insect activity and predation to a gradient of night-time illuminance, simulating skyglow.

Main Methods:

• Assembled insect communities in a fragmented grassland Ecotron experiment.
• Utilized radio frequency identification (RFID) to track insect movement patterns under simulated moon cycles and varying light intensities.
• Assessed predation rates using artificial prey dummies to measure the impact of altered insect activity.

Main Results:

• Even low-intensity skyglow induced a temporal shift, moving insect activity from daytime to nighttime.
• A spatial shift was observed, with insects preferring open habitats at night under ALAN.
• These changes in insect movement indirectly altered predation rates, demonstrating a community-level effect.

Conclusions:

• Artificial light at night significantly alters fundamental ecological processes like movement and predation in insect communities.
• The observed spatio-temporal shifts have critical implications for ecological networks and the functioning of ecosystems.
• ALAN poses a significant threat to global biodiversity and the provision of essential ecosystem services.