DOI: 10.5061/dryad.jq2bvq8ps
title: Severe and widespread reductions in nighttime activity of nocturnal moths under modern artificial lighting spectra

description: 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, using light traps or hand-catching with nets, did affect activity
 in some species, with implications for future research. Finally, further
 experiments found significant activity suppression overall under lighting
 at 1 lx, for white LEDs especially, with some species affected even by
 skyglow levels of white light. Substantial inhibition of activity under
 multiple streetlight-relevant LEDs suggests potential for widespread
 impacts on moth populations.
description: # 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_Script.R
 **Description:** R script containing code for all analyses & plots
 presented in the paper #### File: Activity_MainData.csv
 **Description:** Compiled results of all video analyses for the main
 experiment; each row represents a frame from an analysed video. #####
 Variables * Date: Date each trial started * Moth_ID: Individual ID for
 each moth in the experiment * Light_type: Type of light used - White,
 Broad Amber, Narrow Amber, RGB White, RGB Amber, Natural (Control) *
 Light_intensity: Illuminance (in lux) of light treatment - 0, 0.1, 1, 10 *
 Expt_Start: Starting time for each experiment * X: X coordinate of moth
 position in frame * Y: Y coordinate of moth position in frame * Xcm: X
 coordinate of moth position in frame, converted to cm (using diameter of
 funnel top as scale bar)  * Ycm: Y coordinate of moth position in frame,
 converted to cm (using diameter of funnel top as scale bar)  * OnFunnel,
 OnLid, OnBase: Variables indicating whether moth was resting on the sides
 of the chamber, its lid, or its base respectively. 1 indicates presence of
 moth, 0 absence. * zone1 - zone12: dicates whether position of moth
 overlaps with each of 12 background segments lining the sides of the
 experimental chamber. 1 = presence, 0 = absence * zone0: Indicates whether
 moth position overlaps with no background segments (ie. on base, or on lid
 over base). 1 = position does not overlap with any segments, else 0 *
 Time: Time at each frame * Species: Moth species * Treatment: Combination
 of light type and intensity, defining light treatments used for analysis *
 NightDate: Date object for date of start of trial * RealDate: Date object
 for actual time at each frame (experiments take place overnight, so begin
 on one date and end on the next) * DateTime: Date & time object
 combining date and time at each frame * PlotDate: Dummy variable
 facilitating plotting of experiments run on different days along the same
 axis * Family: Moth family (Erebidae, Geometridae, Noctuidae) *
 CaptureMethod: Method of moth collection - trap (light trap) or net
 (butterfly net at night) * Location: Location of moth collection - Campus
 (university grounds) or Garden (private gardens) * FloorQuarter: Time in
 15 minute intervals, to allow correspondance with weather station records
 * Temperature: Temperature, in °C, at the time of each frame (averaged
 over 15 minute intervals), from weather station on university grounds *
 Humidity: Humidity, in %RH, at the time of each frame (averaged over 15
 minute intervals), from weather station on university grounds #### File:
 Activity_AdditionalData.csv **Description:** Data for additional
 experiments with lower light levels ##### Variables * Most variables as
 above for main dataset. * Frame: Number of video frame analysed *
 Time_Seconds: Time since start of recording, in seconds #### File:
 LightSpectra.csv **Description:** Unprocessed spectra for lights used in
 the experiments ##### Variables * Wavelength: Wavelength (in nm) of each
 measurement, from 300-700nm * White, PC amber, Narrow amber, RGB amber,
 RGB white: Irradiance, in W/m2/nm, measured for each light type. PC amber
 = Broad amber LED #### File: Species_size.csv **Description:** Forewing
 length information (in mm) for species in the main experiment, from Waring
 & Townsend (2018) ##### Variables * Species: Moth species (all 23 in
 main dataset) * ForewingLength_min, ForewingLength_max,
 ForewingLength_mean: minimun and maximum forewing length, from Waring
 & Townsend (2018), and calculated mean #### File:
 supermatrix.proteins.trimmed.fa.treefile **Description:** Phylogenetic
 tree for 21 species in main experiment #### Files:
 BayesMod_withspecies.Rdata, BayesMod_withoutspecies.Rdata
 **Description:** Saved outputs of MCMCglmm models (see code for details)
 ## Code/software All analyses carried out in R v.4.3.2, see
 Analysis_Script.R for all code. Package
 versions: tidyverse_2.0.0, patchwork_1.2.0, ggpattern_1.1.3, rptR_0.9.22, lme4_1.1-35.1, lattice_0.21-9, multcomp_1.4-25, glmmTMB_1.1.10, DHARMa_0.4.6, MuMIn_1.47.5,  AICcmodavg_2.3-3, lubridate_1.9.3, pavo_2.9.0, moonlit_0.1.0, phytools_2.3-0, geiger_2.0.11, phylobase_0.8.12,  phylosignal_1.3.1, ape_5.7-1, MCMCglmm_2.36, emmeans_1.10.0, tidybayes_3.0.7