DOI: 10.5061/dryad.1ns1rn8zp
title: Forest structure and heterogeneity increase diversity and alter the composition of host-parasitoid networks

description: Antagonistic host-parasitoid interactions can be quantified using
 bipartite and meta networks, which have the potential to reveal how
 habitat structural elements relate to this important ecosystem function.
 Here, we analysed the host-parasitoid interactions of cavity-nesting bees
 and wasps, as well as their abundance, diversity, and species richness
 with forest structural elements from 127 forest research plots in
 southwestern Germany. We found that parasitoid abundance, diversity, and
 species richness all increase with host abundance, a potential mediator
 between parasitoids and forest structure. Both parasitoid abundance and
 diversity increased with stand structural complexity, possibly mediated by
 the abundance of hosts. Additionally, parasitoid abundance increased with
 increasing standing deadwood and herb cover. The bipartite networks of
 host-parasitoid interactions showed higher connectance with increasing
 standing deadwood, herb cover, and host abundance. Analyses of
 interactions within the host-parasitoid metanetwork revealed that
 increasing host abundance and decreasing canopy cover diversify the suites
 of interactions present at the plot level. These results demonstrate that
 forest structural elements can improve the stability and resilience of
 host-parasitoid networks by promoting parasitoids and diversifying
 interactions in ecological networks.
description: Data were gathered by sampling cavity-nesting bees and wasps
 using trap nests. The abundance and parasitism events in the trap nests
 were recorded during nest opening, with individuals reared for species
 identification.
description: # Forest structure and heterogeneity increase diversity and alter the
 composition of host-parasitoid networks ### Builder species matrix * Plot
 and corner correspond to the plot and corner where the trap nests
 containing the individuals of each species were collected. * Each species
 column is labeled with the capitalised first letter of the genus followed
 by the species name (e.g. A_antilope represents *Ancistrocerus antilope*).
 The complete species list with full genera names can be found in the
 supplement. * Columns with full genera names contain individuals that
 could not be identified as species. The T_clavicerum_group contains
 specimens that could be identified as only a grouping of similar species.
 Analyses included only specimens that could be identified at the species
 level. ### Parasitoid species matrix * Plot and corner correspond to the
 plot and corner where the trap nests containing the individuals of each
 species were collected. * Each species column is labeled with the
 capitalised first letter of the genus followed by the species name (e.g.
 A_anthrax represents *Anthrax anthrax*). The complete species list with
 full genera names can be found in the supplement. * Columns without
 capitalised genera names followed by species names contain either genus,
 family or superfamily names with no further identification possible.
 Several are subdivided using numbers (e.g. Chrysididae1) to indicate a
 different species, however analyses included only specimens which could be
 identified to species level. ### Parasitism * Plot corresponds to the
 research plot where the builders cells were parasitized by the parasitoids
 listed. Parasitized cells represents the number of brood cells of the
 builder parasitized by the parasitiod in the same rows. ### Total builder
 parasitism * Rows below G_species represent builder species while columns
 after G_species represent parasitoids. The value in each cell represents
 the number of brood cells parasitized. ### Plot geolocations * Plot ID
 represents the plot numbers in the study area. The corresponding latitude
 and longitude values for each plot are listed in the same row. ###
 Environmental variables * plot represents the plot number within the
 ConFoBi study area. Elevation represents the mean elevation value (m) at
 plot level. ENL_transect and SSCI_transect represent the mean of three
 values taken along the NW-CENTER-SE transect of each plot.
 forest-cover_1km represents the proportion (%) of forested area in the 1km
 sorrounding plot centers. herb_cover represents the proportion (%) of area
 covered by herbs. prop deciduous represents the proportion (%) of trees at
 plot level which are deciduous species. mean_canopy_cover represents the
 mean canopy cover (%) calculated from the NW and SE corners of each plot.
 stnd_dw_DBHsum_ds123 represents the cumulative DBH (cm) of standing
 deadwood of decay stages 1, 2 and 3. lying_dw_DBHsum_ds123 represents the
 cumulative DBH (cm) of lyinging deadwood of decay stages 1, 2 and 3. ###
 Interaction cooccurence matrix * The interaction cooccurence matrix is a
 matrix of interaction cooccurences. The interaction partners are shown as
 the first letter of the genus followed by the first three letters of the
 species (e.g. Maca-*Melittobia acasta*, Tfig-*Trypoxylon figulus*,
 interaction=MacaTfig) with parasitoids shown first. This matrix can be
 generated using the previous dataset "Parasitism".