Severe and widespread reductions in nighttime activity of nocturnal moths under modern artificial lighting spectra

Artificial lighting has many negative impacts on nocturnal insects, from harmful phototaxis to disruption of feeding and reproduction. Although comparatively poorly-explored, many detrimental outcomes could be associated with changes in activity. We investigated the effects of different types of light-emitting diode (LED) lighting on activity in multiple wild-caught moth species in three different families. While behaviour under natural conditions varied among species, artificial lighting strongly and largely consistently suppressed activity. In our main experiment, testing 843 moths of 23 species, we found that white LEDs at 10 lx illuminance depressed activity by 85% on average relative to natural nighttime illumination, and even purportedly less harmful amber lighting had similar impacts at the same intensity. There were no differences between the effects of broad-spectrum LEDs and combinations of narrowband LEDs that produce equivalent light for human vision. Collection methods, usi..., , # Severe and widespread reductions in nighttime activity of nocturnal moths under modern artificial lighting spectra

Dataset DOI: [10.5061/dryad.jq2bvq8ps](https://doi.org/10.5061/dryad.jq2bvq8ps)

## Description of the data and file structure

Last updated: 24/11/2025

Study summary: This study tests the effect of artificial light treatments on activity in multiple species of nocturnal moths. Key analyses for the main experiment include 1) differences in overall activity between control and lit treatments, 2) Bayesian phylogenetic modelling of overall activity across treatments, 3) models testing differences in activity patterns between species in the control conditions, and across species between lighting treatments. In addition, smaller datasets are analysed to test 4) impacts of lower light levels on activity patterns in a smaller number of species, and 5) effects of different capture methods.

All analyses carried out in R v.4.3.2.

### Files and variables

#### File: Analysis_Scr..., , **Changes after Dec 3, 2025:** 

A small number of moths in the original dataset were incorrectly labelled as moving in the first frame of their trials; to fix this problem, the \"movement \" columns have now been removed from the raw data, and the movement calculation has been placed within the analysis script, so that the process for calculating movement between frames is explicit, and the resulting data are correct.