We carried out three choice experiments with 6116 nocturnal lepidopteran individuals (95 species, 7 families, 32 075 counts), each replicated 105 times during the seasons of 2 years. Moths were released indoors at the centre of a 10 × 10 m area with different lamps placed at each corner. In experiment 1, lamps emitted ultraviolet (UV) (peak at 365 nm), blue (450 nm), green (520 nm) or cool white (450 and 520 nm) radiation. In experiment 2, UV was replaced by red (640 nm). In experiment 3, we used UV and three mixed radiation lamps of different emission intensities (365–520 nm). We applied a linear mixed effect model to test for differences in attraction to the light sources. Among all counts, 12.2% (males) and 9.2% (females) were attracted to a lamp. Among the lamp counts, 84% were made at the UV lamp in experiment 1. In experiment 2, 63% of the counts were made at the blue lamp. In experiment 3, most counts were made at the strongest mixed radiation lamp (31%), and the UV lamp (28%). Patterns were generally similar across Lepidopteran families, and for both sexes. Moths are clearly preferentially attracted to short‐wave radiation. Even small quantities of UV radiation, emitted, for example, by metal halide lamps and certain mercury vapour tubes, will disproportionately contribute to light pollution. Since blue light also attracts moths strongly, lamps with a low proportion of blue light should be given priority in lighting planning.

http://www.eje.cz cies richness and their presence in habitats where relatively few butterfl y species occur, such as dense forests in Central Europe (Dorow et al., 2019) or high elevation habitats in the Andes, where there is a declining richness in butterfl ies (Despland et al., 2012), but a high diversity of some moth taxa (e.g. Brehm et al., 2016). Secondly, light-trapping has proven an extremely effi cient tool for sampling moths and other nocturnal insects (Montgomery et al., 2021), and it results in far larger numbers of individuals available for analysis than the search for caterpillars (Wirooks, 2006), bait catching (Niermann & Brehm, 2019) or other methods.Conventionally used lamps for light-trapping include mercury vapour lamps or fl uorescent tubes, but LED lamps specifi cally designed for this purpose have become increasingly popular in the last few years. They are attractive to insects, small, lightweight and use little energy (Brehm, 2017;Infusino et al., 2017), allowing the use of lightweight lithium batteries in the fi eld. Artifi cial light at night (ALAN) can have signifi cantly negative effects on populations of insects (Owens et al., 2020), whose populations in Central Europe, for example, have been declining for years (Hallmann et al., 2017). Brehm et al. (2021) showThe number of moths caught by light traps is affected more by microhabitat than the type of UV lamp used in a grassland habitat