Floral colours in a world without birds and bees: the plants of Macquarie Island

• Published in: Plant biology (Stuttgart, Germany) Vol. 18; no. 5; pp. 842 - 850
• Main Authors: Shrestha, M., Lunau, K., Dorin, A., Schulze, B., Bischoff, M., Burd, M., Dyer, A. G.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.09.2016; Wiley Subscription Services, Inc
• Subjects: Angiosperms; Animals; Assembly; Bees; Bees - physiology; Birds; Birds - physiology; Chromatic signal; Color; Cream; Diptera - physiology; Flora; floral colour; Flowers; Flowers - anatomy & histology; Flowers - genetics; Flowers - physiology; fly pollination; Geography; hoverfly (Eristalis); Immigrants; Immigration; Islands; Magnoliopsida - anatomy & histology; Magnoliopsida - genetics; Magnoliopsida - physiology; Models, Biological; Northern Hemisphere; Phylogeny; Plant communities; Plants (botany); Pollination; Pollinators; sub-Antarctic island; Tasmania; Macquarie Island; fly pollination; Chromatic signal; hoverfly (Eristalis); sub-Antarctic island; floral colour
• ISSN: 1435-8603; 1438-8677
• DOI: 10.1111/plb.12456

We studied biotically pollinated angiosperms on Macquarie Island, a remote site in the Southern Ocean with a predominately or exclusively dipteran pollinator fauna, in an effort to understand how flower colour affects community assembly. We compared a distinctive group of cream-green Macquarie Island flowers to the flora of likely source pools of immigrants and to a continental flora from a high latitude in the northern hemisphere. We used both dipteran and hymenopteran colour models and phylogenetically informed analyses to explore the chromatic component of community assembly. The species with cream-green flowers are very restricted in colour space models of both fly vision and bee vision and represent a distinct group that plays a very minor role in other communities. It is unlikely that such a community could form through random immigration from continental source pools. Our findings suggest that fly pollination has imposed a strong ecological filter on Macquarie Island, favouring floral colours that are rare in continental floras. This is one of the strongest demonstrations that plant-pollinator interactions play an important role in plant community assembly. Future work exploring colour choices by dipteran flower visitors would be valuable.