Preference
The two methods we used to determine pollinator preference, RRA (with 0% cutoff) and qAMPseq, did not differ in their estimates of preference (t(599)=-6.8e-10, p=1). Preferences for Clarkia species were significantly different from each other (F(4, 596)=6.210, p<0.001). Bees preferentially carried C. xantianapollen (preference= 0.06±0.04 95% CI) and avoided C. cylindricapollen (preference = -0.09±0.04 95% CI). Bees carried C. speciosa and C. unguiculata at roughly the same frequency these two species occurred in sampled communities, indicating neither preference nor avoidance (C. speciosa t(596)=0.42, p=0.67;C. unguiculata t(596)=0.74, p=0.45; Figure 4, Panel A).
Floral abundance of Clarkia species
Abundances of the four Clarkia species were different (F(3, 47)=6.16; p=0.001). Clarkia cylindrica exhibited significantly higher floral abundances than C. speciosa and C. xantiana .Clarkia unguiculata floral abundances were also slightly higher than those of C. speciosa and C. xantiana , but were not statistically different from any other species. Finally, C. speciosa and C. xantiana exhibited similar floral abundances (Figure S3).