The genus Phaius is distributed mainly in pantropical areas, and most species reported are autogamous. In contrast, Phaius delavayi, an alpine plant endemic to temperate zones of China, is strictly pollinator dependent. Only female workers and males of the bumblebee species B. hypnorum and B. lepidus are effective pollinators. The pollinaria are deposited on top of the head or the prothorax of the pollinators. The different depositions of pollinaria are regarded as an adaptation of the chamber dimensions of the flower to the size of the pollinator. The natural fruit set reported here (24.6-37.1%) suggests that pollination is successful in the deceptive P. delavayi. The yellow perianth and sweet floral scent of P. delavayi are important cues in attracting pollinators, while flowering time and mass population are associated with the process of "learning and avoidance" of the rewardless flowers. This orchid, therefore, employs a deceptive pollination strategy with diverse pollinators and pollinaria depositions rather than autogamy as do its congeners.
Bibliographical noteFunding Information:
We thank Dr. Peter Bernhardt from Saint Louis University, USA, for improving the manuscript, Dr. Xu Huanli from the Chinese Agricultural University for his identification of insects. This study was supported by National Nature Science Foundation of China (30900183) and Southwest University of Science and Technology (07XJGZB17), and by the Co-researching Station of the Institute of Botany, Chinese Academy of Sciences and Huanglong Administration of National Scenic Spots, Sichuan, China.
- Breeding system
- Deceptive pollination
- Functional morphology
- Phaius delavayi
- Pollinaria deposition
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Plant Science