A new efficient bait-trap model for Lepidoptera surveys – the “Oulu” model

To get reliable estimates of biodiversity or relative population sizes, it is important to develop and properly test new survey tools in comparison with previous methods. Here, we introduce a new, effective bait-trap model, viz. the “Oulu” model, for Lepidoptera surveys and monitoring schemes. An extensive field experiment showed that the new bait-trap model captures more individuals and more species than the widely-used “Jalas”model, while the species richness and species composition of the total catches did not differ between the trap models. The differences between the trap models were consistent over time and habitats. We suggest that the “Oulu” model yields high catches because few individuals can escape from the trap. It is thus an effective tool to be used in Lepidoptera surveys and studies.