DOI: 10.5061/dryad.4b8gthtpt
title: Data from: The shape and material of the flight interception trap matter for beetle sampling

description: Beetles are one of the most diverse insect groups, playing vital roles in
 ecosystem functions such as decomposition and pollination. Despite their
 ecological importance, their immense diversity is often undersampled due
 to inconsistent and non-standardised sampling methodologies. We assessed
 the sampling efficiency of flight interception traps using six trap
 designs that differed in shape and panel material in a hemiboreal, mixed
 deciduous forest. We compared the designs in terms of species number,
 abundance, diversity of beetles, and saproxylic beetle species. Trap
 efficiency was evaluated using species accumulation curves. We collected a
 total of 457 beetle species (8,552 individuals) from 51 families,
 including 272 saproxylic species. Although species accumulation curves
 showed signs of flattening, significant differences were observed among
 trap designs. Panels made of soft plastic (polyethylene) outperformed
 those made of hard plastic (polycarbonate) in terms of species diversity
 and the proportion of red-listed species captured. No differences in body
 size were detected among the trap catches. Our results highlight an
 overlooked yet significant effect of panel material in sampling beetle
 communities. The combination of soft plastic panels with a triangular trap
 design significantly improved trap efficiency. This improvement not only
 enhanced the capture of common beetle species but also resulted in a
 higher sampling rate of those of conservation concern. These findings
 underscore the importance of selecting appropriate trap designs to
 increase the accuracy of biodiversity assessments to make better-informed
 conservation decisions. A standardised trap design would enhance
 comparability across studies, improving ecological inferences.
description: # Overlooked design factors in saproxylic beetle sampling: shape and
 material of flight-interception traps
 [https://doi.org/10.5061/dryad.4b8gthtpt](https://doi.org/10.5061/dryad.4b8gthtpt) ## Description of the data and file structure This dataset includes the data and R scripts used to replicate the study by Sbaraglia et al. (in review). The study examines the efficiency of various flight-interception trap designs in capturing beetles, focusing on differences in shape (Cross-pane, Triangular-pane, Rectangular-pane) and material (PE: polyethylene, and PC: polycarbonate). Data were collected in a small hemiboreal forest in Southwestern Norway (4 hectares) during two sampling sessions in July and August 2023. The study area comprised 15 plots, each containing six trap designs representing all combinations of shape and material: Cross-pane PC, Cross-pane PE, Triangular PC, Triangular PE, Rectangular PC, and Rectangular PE. We use ordination methods to evaluate whether species composition differs among trap shapes and materials. When available, the body size of beetles was included in the analysis to test whether different trap designs were more efficient in catching bigger species. Our findings emphasize that often-overlooked factors, such as the type of plastic material used for trap panels, have a significant impact on the number, abundance, and diversity of beetle species captured. Panels made from softer plastic (PE) not only outperformed those made from harder polymer (PC) but also captured a distinct beetle species composition. Triangular and cross-pane panels generally performed better than rectangular ones in terms of species number and beetle abundance, though there was no significant difference in diversity. The combination of triangular panels with PE material yielded the most effective trap design, suggesting that this design is particularly well-suited for capturing beetle assemblages, at least in small areas. The underlying reasons for these differences are discussed in detail in this study. ### Files and variables #### File: env.RDS **Description:** Environmental variables for each trap (n = 90) **trap:** code of the trap **shape:** Panel shape (levels: Cross-pane, Triangular-pane, Rectangular-pane) **material:** Panel material (levels: PE, polyethylene and PC, polycarbonate) **site:** All 15 plots in the area where the traps had been positioned **File: spec.csv** **Description:** Community matrix (trap x species, 90 x 458) including all beetle species recorded during the study. **File: spec_sx.csv** **Description:** Community matrix (trap x species, 90 x 272) containing only saproxylic beetle species. **File: spec_SAC.csv** **Description:** Matrix (6 x 458) with rows representing trap designs and columns representing beetle species, used for calculating species accumulation curves. **File: traits_data.zip** **Description:** ZIP file containing three datasets used to test the effect of body size on beetle catches from different trap designs. The “all_beetles_traits.xlsx” file contains the body size data, while the “all_beetles_trap.xlsx” file includes the number of individuals caught by each trap design. The “sx_trap.xlsx” file is similar to the previous one, but includes only saproxylic beetles. ## Code/software The data and scripts can be opened and run using R software in RStudio. The analysis was performed using R version 4.4.1 and RStudio version 2023.9.1.494. Necessary packages are included in the scripts and should be installed if not already present. The scripts are organized to allow easy replication of the analyses described in the manuscript.