Moth Light Pollution and Nocturnal Invertebrate Welfare

Artificial light at night attracts and disorients moths and other nocturnal invertebrates, causing mortality and reproductive disruption with implications for ecosystem health.

Key Facts

UK moth populations have declined by 28% since 1968, with light pollution identified as a significant contributing factor
Moths attracted to artificial light are killed, exhausted, or prevented from engaging in essential mating and foraging
Caterpillars on streetlit trees feed less efficiently than those in dark areas, reducing survival to pupation
Light-emitting diodes (LEDs) with warm spectrum settings attract fewer insects than blue-rich white LEDs
Dark sky reserves and wildlife-friendly lighting schemes reduce artificial light at night in sensitive areas

Welfare Considerations

Light pollution causes welfare harm to individual moths and other nocturnal invertebrates through exhaustion from circling lights, inability to complete mating flights, and mortality from thermal injury near hot light sources. The population-level effects — reduced reproductive success, disrupted larval development, and population decline — reflect the aggregate of individual welfare harms across millions of animals. Switching to amber or warm-spectrum LEDs, using motion sensors and shields to reduce light spill, and turning off non-essential lighting at night reduce these harms substantially. Dark sky preservation protects the nocturnal environment that entire communities of invertebrates depend on.

What You Can Do

Switch outdoor lighting to warm-spectrum amber LEDs and use motion sensors to minimise unnecessary illumination
Turn off or shield lights that illuminate gardens and greenery at night during moth flying seasons
Support dark sky designation applications for rural areas with low existing light pollution
Participate in national moth recording nights and garden moth trapping surveys to monitor population trends