Moth light traps perform better with vanes : A comparison of different designs

Many light trap designs exist in the field of applied and basic entomology for catching moths, yet a robust comparative analysis of structural designs of such traps is lacking. Our study compares the performance of three different trap designs to assess the effect of presence/absence of vanes and their colour on trapping efficiency. LepiLED lamps were used in all traps as the light source. We hypothesized that traps with vanes (white and black) would perform better than the same trap with rods, since it improves flight interception of insects. Furthermore, we expected that between the two designs with vanes white would be more efficient than black due to a higher radiation emission and better visibility. The study was conducted between July and September 2021 at two locations in the nature reserve Jenaer Forst (Jena, Germany, N 50.926694, E 11.556583). At each location, we sampled in three understorey sites parallelly. The abundance, diversity and body size of 4432 moths belonging to 170 species and 12 different families were analysed. Traps with white vanes performed best with 10.5% more individuals and 7% more species than the trap with black vanes and with 19% more individuals and 16% more species than the traps with rods. Differences were significant between the two vane traps against rods, for both individuals and species, but differences between the two vane traps were not. In addition, traps with white vanes and with rods were tested indoors under controlled conditions for selected species. In four out of ten species, significantly more individuals were collected in the vane traps. We conclude that the use of vanes as a flight interception tool is important for improving the trapping efficiency. The colour of vanes is also likely to play a role because of an overall higher radiation emission and better visibility for insects.