Evolution of ornithophily in East Asia
Character evolution of floral traits and pollination syndrome in the genus Aeschynanthus (Gesneriaceae)
The degree of evolutionary specialization between nectar-feeding birds and plants varies greatly among regions. Bird-pollinated is almost entirely absent in Asia north of the Himalayas in the absence of nectar specialists. The few reported case studies are rather generalized pollination system with unrestricted corolla and also pollinated by other insects, leading to the doubt whether exclusively bird-pollinated plants could exist in East Asia.
Aeschynanthus acuminatus from Mt. Er-Ge, Taiwan, with its stunted and wider corolla tube and yellow greenish color.
Aeschynanthus chiritoides with white and bell-shape flowers.
Aeschynanthus Jack (Gesneriaceae), a genus comprising approximately 160 species, mainly in subtropical Southeast Asia, is one of few ornithophilous lineages distributed in East Asia.
The members of this genus usually have typical bird-pollination syndromes such as red and long floral tubes, protruding and paired stamens, and large amount and dilute nectar.
However, the pollination observation and research are extremely lacking, leaving the question of whether the nectar specialists, sunbirds, are their actual pollinators.
Besides, few exceptions on the edge of the distribution of the genus just show some extraordinary floral characters. For example, A. acuminatus has a short and stunted corolla tubes with unusual greenish color. The pollinators were once expected to be moths or bats due to the shifts of floral shapes and color.
Other interesting examples include A. chiritoides from southern Yunnan and northern Vietnam. The species name comes from the white and bell-shaped corolla tubes resembling the genus Chirita also from Gesneriaceae. With these completely different pollination syndromes, it would be regarded as bee pollination.
During the undergraduate study at National Taiwan University, I started with the pollination ecology of the only species of the genus in sunbird-absent Taiwan, A. acuminatus. With the astonishing discovery of its pollination system, several exciting further works on the tempo and spatial mode of evolution of ornithophily could be expected.
Current Work
Specialized pollination system of Aeschynanthus acuminatus (Gesneriaceae) by generalist passerines in sunbird-absent East Asia
This work is in collaboration with Kai-Hsiu Chen (current master student at Université de Lausanne) and Dr. Chun-Neng Wang.
Focusing on the pollination biology and floral characteristics of Aeschynanthus acuminatus. Directly observe the pollinators of A. acuminatus in Taiwan, evaluate the pollination efficiency, compare morphological characters, and measure the pollination syndromes quantitatively.
Have a look!
This project was granted by the Ministry of Science and Technology - Undergraduate research program.