Monolecty in the presence of the closest relative species in the region.
(a) Flowering phenology of the closely related Cistus crispus and C. albidus in a woodland patch where both co-occur (corolla diameter of 5 and 6 cm, respectively). In this site, several Flavipanurgus venustus bees were always observed on C. crispus flowers (n = 53 observations; the green area denotes the local flight activity period of the bee). (b) Reflectance (%, mean ± sd) of C. crispus and C. albidus petals (n = 17 flowers per species). Whereas the flowers of C. crispus reflect a large fraction of ultraviolet (UV) light, the flowers of C. albidus only reflect a negligible fraction. Note how, in the left photo, a female F. venustus is collecting C. crispus pollen in its scopa while a male (upper-left corner) is approaching for mating.