DOI: 10.5061/dryad.h70rxwdvx
title: Warmer temperatures reinforce negative land-use impacts on bees, but not on higher insect trophic levels

description: Climate and land-use change are major drivers of insect decline, yet their
 interactive effects on insect richness and abundance, especially across
 trophic levels, remain poorly understood. Here, we investigate how
 temperature and land use shape insect communities across spatial scales
 and trophic levels, from flowering plants and cavity-nesting bees to
 hunting wasps, their antagonists, and parasitism rates. Using trap nests
 and a space-for-time approach, we surveyed 179 plots spanning four habitat
 types (forest, grassland, arable land, and settlements) across 60 study
 regions in Germany covering semi-natural, agricultural, and urban
 landscapes. Bee richness and abundance responded to climate–land-use
 interactions across spatial scales, being higher with warmer local daytime
 temperatures and overall warmer climates, but only in less intensive land
 uses. In contrast, elevated nighttime temperatures negatively affected
 bees. Higher trophic levels benefited more consistently from warmer
 climates than lower trophic levels and were less affected by high local
 daytime and nighttime temperatures. Parasitism rates were lowest in arable
 land but similar across habitats within semi-natural regions, suggesting
 that landscape-scale processes buffer local effects. Our findings
 underscore the importance of considering nighttime temperatures for
 diurnal insects and suggest that rising temperatures may exacerbate the
 negative impacts of land use on pollinators.
description: # Warmer temperatures reinforce negative land-use impacts on bees, but not
 on higher insect trophic levels
 [https://doi.org/10.5061/dryad.h70rxwdvx](https://doi.org/10.5061/dryad.h70rxwdvx) ## Description of the data and file structure Data collected on 179 plots within 60 regions from March to September 2019 as part of the LandKlif project. ### Files and variables #### File: Bee\_Sp\_TrapNests.csv **Description:** bee species found in the plots and used to produce the rarefaction interpolation curves of Fig. S1.2. #### File: Wasp\_Sp\_TrapNests.csv **Description:** wasp species found in the plots and used to produce the rarefaction interpolation curves of Fig. S1.2. #### File: Data\_local\_TN.csv **Description:** response and explanatory variables at the local scale. ##### Variables * PlotID: unique identifier of each study plot * RegionID: unique identifier of each study region * POINT_X: longitude of the plot point of this region, coordinate system as "DHDN_3_Degree_Gauss_Zone_3" * POINT_Y: latitude of the plot point of this region, coordinate system as "DHDN_3_Degree_Gauss_Zone_3" * NoTraps: number of trap nests per plot that could be used for the study * flower_richness: total number of angiosperm species in a 200-m buffer radius around study plots * bee_richness: number of morphospecies of bee hosts in the plot * bee_abundance: number of bee brood cells per plot * wasp_richness: number of morphospecies of hunting wasps in the plot * wasp_abundance: number of hunting wasp brood cells per plot * host_richness: number of morphospecies of trap-nesting bees and hunting wasps in the plot * host_abundance: number of bee and wasp brood cells per plot * antagonist_richness: number of taxonomic groups of antagonists in the plot * antagonist_abundance: number of brood cells with hosts killed by predators, cleptoparasites, or parasitoids in the plot * percentage_parasitism: number of hosts killed by antagonists divided by number of hosts * habitat: local habitat type of the plot * RLU: dominant regional land-use type * temp_maxdaytime: means of the maximum daytime temperature recorded from March to September 2019 * temp_minnighttime: means of the minimum nighttime temperature recorded from March to September 2019 * regional_temperature: 30 year means of the monthly averaged mean daily air temperature in °C in 2 m height above ground from 01.01.1981 - 31.12.2010 #### File: Data\_regional\_TN.csv **Description:** response and explanatory variables at the the regional scale. ##### Variables * RegionID: unique identifier of each study region * X: longitude of the center point of this quadrant, coordinate system as "ETRS89 / UTM zone 32N" * Y: latitude of the center point of this quadrant, coordinate system as "ETRS89 / UTM zone 32N" * NoTrapsRegion: number of trap nests per region that could be used for the study * Reg.flower_richness: total number of angiosperm species recorded in the three plots a region * Reg.bee_richness: total number of bee species recorded in the three plots a region * Reg.bee_abundance: total number of bee brood cells in the region * Reg.wasp_richness: total number of wasp species recorded in the three plots a region * Reg.wasp_abundance: total number of hunting wasp brood cells in the region * Reg.host_richness: total number of host species recorded in the three plots a region * Reg.host_abundance: total number of bee and hunting wasp brood cells in the region * Reg.antagonist_richness: total number of antagonist taxonomic groups recorded in the three plots a region * Reg.antagonist_abundance: total number of brood cells with hosts killed by predators, cleptoparasites, or parasitoids in the region * percentage_parasitism: number of hosts killed by antagonists in the region divided by number of hosts in the region * RLU: dominant regional land-use type * regional_temperature: 30 year means of the monthly averaged mean daily air temperature in °C, 2 m height above ground from 01.01.1981 - 31.12.2010 * Forest_proportion: proportion of forest area in the region * Agriculture_proportion: proportion of cropland area in the region * Urban_proportion: proportion of urban area in the region #### File: Temp\_comparison\_2019\_long\_term.csv **Description:**  ##### Variables * PlotID: unique identifier of each study plot * time_period: spring (March–May) or summer (June–August) of 2019 and 1981-2010 * mean_temperature: mean temperature values of each time period. Temperatures are derived from raster data and represent mean air temperature at 2 m height above ground * season: spring or summer ## Code/software The code used to produce the results is attached in a Markdown file.