Catch effectiveness, complementarity and costs of five sampling techniques for flying insects across different land use types

Abstract

In times of insect decline, sampling programmes are fundamental for monitoring and protecting insect populations. Different types of traps are currently used for insect monitoring, which makes trap selection more challenging and impedes the comparability of results among methods. Trap comparisons, which reveal the species richness, complementarity and costs for the materials and operation of different trap types, help identify sampling designs that ensure (cost-)efficient insect capture. For our study, we selected five sampling techniques for flying insects: canopy Malaise traps (CAMTs), caterpillar traps, branch sampling and white and blue pan traps. We compared them across four habitats (forest, margin and centre of short rotation coppices and maize fields) using detected Barcode Index Numbers (BINs). Comparisons were performed for the total arthropod community and separately for the Coleoptera, Diptera, Lepidoptera and Hymenoptera orders. Our trap selection demonstrated high complementarities of 66–77% depending on the habitat. Our findings indicate that, in most cases, CAMTs, branch sampling and caterpillar traps were the most effective and cost-efficient options when used individually or in combination. Caterpillar traps were particularly effective in forests and detected far more taxa than only lepidopterans. Pan traps demonstrated the lowest species richness and poorest cost efficiency. Nevertheless, it is important to consider individual groups and habitats, such as Diptera, Coleoptera and maize fields, for which pan traps can also be an effective method.