Using the environmental light field method for measuring biologically relevant light characteristics at the household scale

The regular variations of light in the natural light cycle serve as one of the most important cues for the timing of biological events in organisms. The increasing prevalence of artificial light at night (ALAN) alters the natural light cycle and has been found to have harmful effects on human, wildlife, and environmental health. Although several techniques can be employed to measure ALAN, most cannot measure spectral information and, therefore, quantifying ALAN for ecological applications remains a challenge. Here we use the newly described environmental light field (ELF) method to characterise the artificial light environment inside and immediately outside houses in rural settlements (South Africa, Mozambique, and Uganda) as the lighting present in these areas will likely play a role in affecting people's risk of being infected by vector‐borne diseases. The ELF method characterises the light detected by the animal retina, and so offers a powerful tool to compare artificial lighting conditions detected by organisms, taking environmental influences into account. We found light‐emitting diode (LED) lighting to be the dominant lighting type across our study sites. We recorded large variability in both the intensity and spectral composition among houses, with different structural properties and light types present. Given its importance as a disease vector, we use a case study of anopheline mosquitoes, several of which act as malaria vectors, and compare how light characteristics influencing key mosquito behaviours differ among regions and houses. Houses with lights that emit higher proportions of blue and UV light may attract more of certain anopheline species, while repelling others. Higher light intensities inside houses may attract more anophelines, but reduce their feeding. How changes in mosquito attraction and feeding translate into changes in real‐world communities and disease transmission, however, remains unknown.