Partial dependence plots for explanatory variables in the BRT model.

<p>Y axes were centered on the mean of the response variable. The relative contributions of explanatory variables averaging overall BRT model ensembles are showed as the percentage values in parentheses.</p

Three periods of foraging behavior of honey bees on a squash flower.

<p>(A) top view; (B) lateral view.</p

Dated estimate of phylogeny for species of the subgenus <i>Megabombus</i>.

<p>From Bayesian analysis of COI barcodes, using single samples selected to represent each of the species from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.g002" target="_blank">Fig 2</a> and using the birth-death process for speciation on the tree. The tree is dated in Ma by setting the date for the divergence with the <i>Mendacibombus</i> outgroup to 34 Ma [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.ref033" target="_blank">33</a>]. Values at each node: posterior probability / age in Ma. Nodes with support <i>p</i>≥0.8 show 95% confidence limits for the date estimate as grey bars; nodes with support <i>p</i><0.8 have the values shown in grey; nodes with support <i>p</i><0.66 are shown collapsed. The vertical gray line show the 1.3 Ma position to distinguish between the two time periods. The extreme food specialization species name with under dashed line.</p

Length of time (mean ± se) used by a honey bee to examine and collect the floral resources.

<p>(A) pistillate flowers; (B) staminate flowers. Numbers in parentheses indicated sample size. *** < 0.001.</p

Elapsed time (mean ± se) of the Period for Departure-Arrival Route.

<p>(A) pistillate flowers at the fields within the HN habitats; (B) staminate flowers at the fields within the HN habitats; and (C) pistillate and staminate flowers at the fields within the LN habitats. Numbers in parentheses indicate sample size. *** < 0.001; * < 0.05; ns: not significant.</p

Earlier estimate of phylogeny for species of the subgenus <i>Megabombus</i>.

<p>From combined Bayesian analysis of five genes: (mitochondrial) 16S, and (nuclear) opsin, ArgK, EF-1α, and PEPCK [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.ref011" target="_blank">11</a>]. Values at each node: posterior probability / age in Ma. Redrawn with nodes with support <i>p</i><0.66 shown collapsed. Date estimates in millions of years before the present (Ma) are taken from Hines (her <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.g002" target="_blank">Fig 2</a>) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.ref033" target="_blank">33</a>]. Species concepts and names are adjusted according to the interpretations of the present study.</p

Behavioral responses of a newly-arrived bee to flowers occupied by conspecifics or heterospecifics.

<p>(A) responses of a newly-arrived bee in the fields within the HN habitats; (B) responses of a newly-arrived bee in the fields within the LN habitats. Numbers in bars showed the sample size.</p

Dated estimate of phylogeny for species of the subgenus <i>Megabombus</i>.

<p>From Bayesian analysis of COI barcodes, using single samples selected to represent each of the species from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.g002" target="_blank">Fig 2</a> and using the birth-death process for speciation on the tree. The tree is dated in Ma by setting the date for the divergence with the <i>Mendacibombus</i> outgroup to 34 Ma [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132358#pone.0132358.ref033" target="_blank">33</a>]. Values at each node: posterior probability / age in Ma. Nodes with support <i>p</i>≥0.8 show 95% confidence limits for the date estimate as grey bars; nodes with support <i>p</i><0.8 have the values shown in grey; nodes with support <i>p</i><0.66 are shown collapsed. The vertical gray line show the 1.3 Ma position to distinguish between the two time periods. The extreme food specialization species name with under dashed line.</p

Growing degree days of collecting site for six <i>Megabombus</i> species (Boxplots show the median, upper and lower quartiles, 99% confidence limits and outliers).

<p>Growing degree days of collecting site for six <i>Megabombus</i> species (Boxplots show the median, upper and lower quartiles, 99% confidence limits and outliers).</p

Distribution of diversity for the subgenus <i>Megabombus</i> among equal-area grid cells.

<p>Data for China are updated from the review by Williams 1998 using the IAB collection, and exclude records for known introductions (New Zealand, South America, Iceland). The grid is based on longitudinal intervals of 10°, which are used to calculate graduated latitudinal intervals to provide equal-area cells (each cell of area approximately 611,000 km²). Grey scale (right) with equal-interval richness classes. Cylindrical orthomorphic projection (excluding Antarctica) with north at the top of the map.</p