Heterostylous morph differences in pollen transfer and deposition patterns in Primula sieboldii on a visitation by a queen bumblebee, measured with a semi‐natural experimental system

Abstract

Abstract Under a semi‐natural setting the between‐morph pollen exchange patterns were studied in distylous Primula sieboldii flowers by measuring pollen removal from the anthers on a single visit by a Bombus diversus tersatus queen, and stigmatic pollen deposition along the sequence of the visitation of the opposite‐morph flowers by the bee. Despite the twofold larger number of pollen grains produced in a single flower of the long‐styled morph compared to that of the short‐styled morph, no significant difference in pollen removal from a flower was found between the morphs. The stigmas of the long‐styled morph received significantly more opposite‐morph pollen grains than those of the short‐styled morph on a single visit by the bee. Sufficient legitimate pollen grains, surpassing the ovule number, were loaded on the stigmas of 27% and 17% of visited flowers of the long‐ and short‐styled morphs, respectively. The short‐styled morph could more efficiently donate pollen to the opposite morph stigmas than the long‐styled morph.