Data from: Altitudinal flower size variation correlates with local pollinator size in a bumblebee-pollinated herb, Prunella vulgaris L. (Lamiaceae)

The influence of locally different species interactions on trait evolution
is a focus of recent evolutionary studies. However, few studies have
demonstrated that geographically different pollinator-mediated selection
influence geographic variation in floral traits, especially across a
narrow geographic range. Here, we hypothesized that floral size variation
in the Japanese herb Prunella vulgaris L. (Lamiaceae) is affected by
geographically different pollinator sizes reflecting different pollinator
assemblages. To evaluate this hypothesis, we posed two questions. 1) Is
there a positive correlation between floral length and the proboscis
length of pollinators (bumblebees) across altitude in a mountain range? 2)
Does the flower–pollinator size match influence female and male plant
fitness? We found geographic variation in the assemblage of pollinators of
P. vulgaris along an altitudinal gradient, and, as a consequence, the mean
pollinator proboscis length also changed altitudinally. The floral corolla
length of P. vulgaris also varied along an altitudinal gradient, and this
variation strongly correlated with the local pollinator size but did not
correlate with altitude itself. Furthermore, we found that the size match
between the floral corolla length and bee proboscis length affected female
and male plant fitness and the optimal size match (associated with peak
fitness) was similar for the female and male fitness. Collectively, these
results suggest that pollinator-mediated selection influences spatial
variation in the size of P. vulgaris flowers at a fine spatial scale.