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Functional mismatch in a bumble bee pollination mutualism under climate change

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Science  25 Sep 2015:
Vol. 349, Issue 6255, pp. 1541-1544
DOI: 10.1126/science.aab0868
  • Fig. 1 Change in tongue length for B. balteatus and B. sylvicola on Mount Evans, Niwot Ridge, and Pennsylvania Mountain.

    (A) B. balteatus. (B) B. sylvicola. Bars represent least squares means >± SE. (15). Asterisks denote significant differences (P < 0.05) between means. Dagger denotes a trend (P < 0.06).

  • Fig. 2 Changing bumble bee community composition, bumble bee tongue length distributions, and tube depth distributions of visited flowers over time.

    (A and B) Bumble bee community composition. (C and D) Bumble bee tongue length. (E and F) Flower tube depth distribution. Bombus species abundance in alpine communities is indicated by the proportion of total foragers (15). Species are ordered by increasing tongue length [in (A), species’ names follow (18)]. Bimodality of the density functions (15) indicates that bumble bee communities contain two predominant phenotypes, short-tongued and long-tongued [(C) and (D)]. (E) and (F) show the tube depth density functions for flowers visited by, respectively, B. balteatus and B. sylvicola in the Front Range [Mount Evans and Niwot Ridge (15)]. For tongue length [(C) and (D)] and tube depth [(E) and (F)], representative density functions for simulated communities (15) are shown.

  • Fig. 3 Change in flower abundance at landscape and local scales along a 400-m altitudinal gradient on Pennsylvania Mountain.

    (A) Map showing areas where PFD decreased (1.95 km2), is stable (1.29 km2), and increased (0.10 km2). Unshaded (excluded) areas contain cliff, talus, mining disturbance, and subalpine forest. (B) PFD (mean >± SE) for plots in krummholz (KRUM); tundra slopes (SLOPE); wet meadow (SWALE), false summit (FSUMMIT); and summit (SUMMIT) habitats (N = 6 species; F4,385 = 5.55, P = 0.0002). Asterisks indicate significant differences at P < 0.05. (C) Total flower production (in millions) is the product of total surface area for (A) each habitat (table S5) (15) and (B) mean PFD.

  • Fig. 4 Relative advantage of generalizing as a function of flower density and the proportion of deep flowers in the community.

    Outcomes with flight speed of 0.5 m s−1 are shown (15). The generalist is favored when its relative advantage is >1 (pink shading).

  • Functional mismatch in a bumble bee pollination mutualism under climate change

    Nicole E. Miller-Struttmann, Jennifer C. Geib, James D. Franklin, Peter G. Kevan, Ricardo M. Holdo, Diane Ebert-May, Austin M. Lynn, Jessica A. Kettenbach, Elizabeth Hedrick, Candace Galen

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S4
    • Tables S1 to S9

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