DOI: 10.5061/dryad.1rn8pk0q4
title: Increasing agricultural habitat reduces solitary bee offspring number and weight in apple orchards through reduced floral diet diversity and increased fungicide risk

description: 1. Threats to bee pollinators such as land use change, high pesticide
 risk, and reduced floral diet diversity are usually assessed
 independently, even though they often co-occur to impact bees in
 agroecosystems. 2. We established populations of the non-native mason bee
 O. cornifrons at 17 NY apple orchards varying in proportion of surrounding
 agriculture and measured floral diet diversity and pesticide risk levels
 in the pollen provisions they produced. We used path analysis to test the
 direct and indirect effects of different habitats, diet diversity, and
 pesticide risk on emergent female offspring number and weight. 3. Our
 results showed that high proportions of agricultural habitat surrounding
 bee nests indirectly reduced the number of female offspring produced, by
 reducing floral diet diversity in pollen. 4. When proportion agriculture
 surrounding bee nests was high, bees collected increased proportions of
 Rosaceae in their pollen provisions, which marginally
 (0.05&lt;p&lt;0.1) increased fungicide risk levels in pollen,
 which, in turn, marginally reduced female offspring weight. In contrast,
 female offspring weight increased as proportion surrounding open habitat
 (wildflowers, grassland, pasture) increased, but this effect was not
 influenced by proportion Rosaceae or fungicide risk levels in pollen. 5.
 Synthesis and Applications: To promote healthy O. cornifrons populations
 in apple, we must maintain floral resource diversity and open habitats,
 while reducing fungicide risk levels and agricultural habitats. More
 broadly, our results show that land use change, in the form of increasing
 agricultural habitat, can negatively impact bee populations in
 agroecosystems indirectly through multiple, simultaneous threats. We must
 strive to understand these complex interactions between simultaneous
 threats to maintain healthy bee populations in agroecosystems, where we
 rely on them for pollination.
description: Please refer to the
 "Materials and Methods" section of the associated article, as
 well as Appendix S1 and S2 of the Supporting Information, where you will
 find all information related to methodogy and data processing.
description: Please see the “Materials
 and Methods” section of the associated article, as well as Appendix S1 and
 S2 of the Supporting Information for details on how these data were
 collected and processed. This “Read Me” information walks you through the
 data-set. The Site_Code is a two-letter code based on the apple orchard
 site where data were originally collected. We do not add lat/long
 information here, in order to respect the privacy of our participating
 growers. Actual orchard area in square meters (see column “Orchard Area
 m2”) was also measured by ground-truthing the area on a map in qGIS (see
 methods and Figure S3 in the Supplemental Materials). There were tree time
 points per site, corresponding to distinct calendar dates. Site letters
 here correspond to letters used in the Supplemental Materials of the MS.
 They were re-coded from the original 2-letter codes to further protect
 site identity. The landscape metrics complied
 using the CropScape data layer are abbreviated here as follows: “Ag” for
 Agriculture and “WetShrub” for wetland and shrubland. “Other” refers to
 barren and open water habitats. Each habitat type (see method for what
 constitutes each type) was measured at different meter radii surrounding
 bee nests, denoted here by “-###m” after the habitat type. “Apples” refers
 to surrounding apple area at our sites, as measured by the crop-scape data
 layer. The total
 emerged male and female offspring for each time point are shown here, as
 well as the proportion of female offspring per both male and female
 offspring. The average weight (in grams) of up to ten (or fewer if fewer
 were produced) male and ten female offspring per site are also recorded
 here. Finally, proportion larval mortality (as recording using
 x-radiography of bee nests – see methods) per time point is shown here.
 The average temperature between time points (see methods) in Celsius is
 shown here. As explained in the methods, the total nest tubes collected
 for reproduction and for pollen analysis per time point are recorded here,
 as well as the total number of pollen provisions complied for pollen
 (pesticide and diet diversity) analysis in equal amounts per nest tube
 (see methods). The average fungicide and
 insecticide risk measured in percent hazard quotient (see methods) is
 shown here, along with the “herb risk”, or herbicide risk. For more
 information about pesticide risk, the chemicals tested and detected, and
 the parts per billion found, please see Table S2, S3, and S6 in the
 Supplemental Materials. The proportion of pollen from
 each of the 11 floral families detected in pollen provisions is shown
 here, based on 300 grain counts per time point (see methods). Finally,
 floral richness, Shannon diversity index, and evenness at the family level
 were calculated and are presented here. Missing values (denoted as “NA”)
 are also explained in the Materials and Methods and Appendix S1 and S2 of
 the associated article and its Supporting Information,
 respectively.