Effects of species traits on the catchability of butterflies with different types of Malaise traps and implications for total catch biomass

Abstract Increasing evidence for insect biodiversity decline requires an identification of the causes but also an improved understanding of the limitations of the various underlying sampling methods. Trap comparisons foster comparability of larger-scale biodiversity studies by providing a deeper understanding of the variations in species abundances and trait compositions due to variations in trap characteristics. In our study, we compared five Malaise trap types on their catchability of butterfly species and noctuid moths and examined for the butterflies how this can be related to traits. We showed marked differences in species and trait occurrence in the samples of the different trap types which seemed to be influenced by roof colour (white, black) and trap shape (Townes trap: high, wide roof, Bartak trap: low, narrow roof). We found most butterfly species and most butterfly biomass in the white-roofed Townes trap. All butterfly traits were represented with most individuals in this trap. Compared with its black counterpart, it showed increased catches for pale butterflies and forest species. We found that dark-roofed traps captured fewer butterfly species and had a lower butterfly biomass. Townes traps captured more butterflies with larger wingspans, egg-laying locations higher above ground, and tree feeding behaviour compared to Bartak traps. Depending on the season and habitat, the differences in species capture may affect overall insect biomass.