On average, do we know what kind of lights attract moths best? LED, filament bulb, candle...?
And what about colour? Does that matter?
Multiple studies have found moths along with most other insects to be significantly more attracted to lamps that emit smaller wavelengths such as ultraviolet (UV). Some species of moth appear to be more attracted to shorter wavelengths than others. The visibility of the light to the moth, the distance between the moth and light, and the brightness of the light are also contributing factors in whether the moth will be attracted to light.
Langevelde et al. found that actinic lamps with a mean weighted wavelength of 382 nm (lamp type a) were the most attractive to moths in both abundance and species richness when compared to other lamps that emitted longer wavelengths. The lamp types used along with the data they collected are displayed below:
Hsiao, H. (1972). The attraction of moths (Trichoplusia ni) to infrared radiation. Journal of Insect Physiology, 18(9), 1705-1714. doi:10.1016/0022-1910(72)90100-x
Owens, A. C., & Lewis, S. M. (2018). The impact of artificial light at night on nocturnal insects: A review and synthesis. Ecology and Evolution, 8(22), 11337-11358. doi:10.1002/ece3.4557
Somers-Yeates, R., Hodgson, D., McGregor, P. K., Spalding, A., & Ffrench-Constant, R. H. (2013). Shedding light on moths: shorter wavelengths attract noctuids more than geometrids. Biology Letters, 9(4), 20130376-20130376. doi:10.1098/rsbl.2013.0376
Truxa, C., & Fiedler, K. (2012). Attraction to light - from how far do moths (Lepidoptera) return to weak artificial sources of light? European Journal of Entomology, 109(1), 77-84. doi:10.14411/eje.2012.010
Van Langevelde, F., Ettema, J. A., Donners, M., WallisDeVries, M. F., & Groenendijk, D. (2011). Effect of spectral composition of artificial light on the attraction of moths. Biological Conservation, 144(9), 2274-2281. doi:10.1016/j.biocon.2011.06.004