Figure 1. Study species and the study sites. (a) Yellow flower and (b)
red flower of A. buergeriana var. buergeriana . (c)
Measurement of floral spur length and bumblebee size. (d) Locations of
the 16 surveyed populations in the four mountain regions (populations
are indicated by ”Population no. Region abbreviation-altitude [in
meters]”. The size of the purple circle at each site indicates the
average spur length of the flowers at that site (spur length was not
observed in the 10 ON-1340 population).