Many plants conceal their pollen to require pollinators to use specialized methods, such as acoustic resonance pollen ejection, to achieve pollination. Pollinators with such capabilities are predominantly bees (buzz pollination), with the bumblebee being the most representative. In the process of buzz pollination and nectar exchange pollination, the interaction patterns and mechanisms between pollinators and floral traits differ significantly. In buzz pollination, the patterns of interaction between pollinators and floral resources remain poorly understood.

The upper corolla of some Pedicularis species forms a specialized and innovative trait (i.e., a twisted beak-like structure) that envelops the anther, forcing pollinators such as bumblebees to release pollen through a "buzzing" method.

Focusing on five beaked Pedicularis species within the community that do not produce nectar and their three primary pollinating bumblebees, the Plant Reproductive Ecology Group at Wuhan Botanical Garden of the Chinese Academy of Sciences conducted a five-year field experiment to investigate in depth the factors that influence bumblebee flower-visiting preferences.

The research shows that when bumblebees use the same buzzing frequency to access different plants to obtain pollen, their flower-visiting preferences depend primarily on the abundance of floral resources and do not have a specific species preference. When bumblebees use different buzz frequencies to visit flowers of different plants, their flower-visiting preferences maintain a specific species preference, primarily for plants with greater pollen rewards.

This study elucidates the interdependent patterns of pollinator-flowering plant interactions based on acoustic traits, enriching the scientific understanding of the diversity of plant breeding strategies.

This study was published in Entomologia Generalis, titled "Bumblebees' flower preferences are associated with floral abundance and buzz frequency when buzz-pollinating co-flowering plants".

HUANG Wen is the first author, Prof. YANG Chunfeng and Associate Professor YE Zhongming are the co-corresponding authors, with the guidance of Prof. Mario Vallejo-Marín from Uppsala University, Sweden, and Prof. David W. Inouye from Rocky Mountain Biological Laboratory, USA. This research was supported by the National Natural Science Foundation of China.

A conceptual framework showing the interactions between bumblebees’ buzz-pollination strategy and flower preferences on co-flowering buzz-pollinated species in a community leading to partitioning of floral resources use (Image by HUANG Wen)