Fig 1.
Land use within a 2km buffer area of the study site in Wayne National Forest, New Straitsville, OH.
Location in Ohio marked with a star on state map. The extent of current surface and underground coal mining operations and abandoned mine lands in Ohio are shown in dark gray.
Table 1.
Bees sampled by species, social caste, and date.
Table 2.
Flowers sampled by species and date.
Fig 2.
Habitat trends in natural abundances of C and N stable isotopes in bee abdomens and flowers.
(a) bee ∂13Clipid normalized, (b) flower ∂13C, (c) bee ∂15N, (d) flower ∂15N. The center line represents group median, with boxes showing upper and lower quartiles. The bars show value range. Bee sample sizes were as follows: field n = 25, edge n = 64, forest n = 0. Flower sample sizes were as follows: field n = 10, edge n = 16, forest n = 6.
Fig 3.
Bee abdomen isotope composition by taxonomic and social caste groups.
(a) Andrena carlini (AprMay) are shown as dark blue squares, A. crateaegi (Jun) as light blue. (b) Halictus ligatus (Jun–Aug) are shown as dark purple squares, H. confusus (Jul) as light purple, (c) Bombus overwintered spring queens (AprMay) are shown as white squares, summer queens-of-the-year (Jul–Aug) as black, and summer workers (Jun–Aug) as gray. Bombus isotope values did not differ significantly by species. Bee ∂13C was lipid normalized following (McConnaughey and McRoy (1979).
Table 3.
The effects of habitat, genus, and social caste on wild bee abdomen C and N isotope composition.
Fig 4.
Seasonal trends in natural abundances of C and N stable isotopes in Bombus worker abdomens and flowers.
(a) bee ∂13Clipid normalized, (b) flower ∂13C, (c) bee ∂15N, (d) flower ∂15N. Samples collected at the end of April were combined with those from the beginning of May. The center line represents group median, with boxes showing upper and lower quartiles. The bars show value range. Bombus worker sample sizes were as follows: June n = 16, July n = 22, August n = 9. Flower sample sizes were as follows: AprMay n = 15, June n = 5, July n = 9, August n = 3.
Table 4.
The effects of habitat, month, and growth form on flower C and N isotope composition.
Fig 5.
Estimated contribution of field, forest, and edge flowers to bee diets.
Isospace mixing model plot generated using MixSIAR. Error bars indicate ± 1 SD (combined error for potential food sources and trophic discrimination factor).
Table 5.
Predicted proportion diet contributions of field, edge, and forest flowers to bee abdomen C and N isotope composition.