In my new book Birds & Flowers: An Intimate 50 Million Year Relationship I spend a bit of time discussing the idea of the bird pollination syndrome that we refer to as ‘ornithophily’, its limitations, and the fact that it has two distinct meanings that are often conflated. One of the problems with ornithophily, and indeed all of the syndromes, is that historically it’s sometimes blinkered scientists to the extent that they only look at the flower visitors that are “right” for the syndrome, ignoring the rest or dismissing them as “secondary pollinators”, a term I dislike.
Why do I dislike that term? Because it fails to capture the complexity of flower-pollinator interactions and relegates an important component of plant reproduction to a subsidiary role. I could go on about this at some length, but if you’re interested in discovering more, look at pages 62-65 of Birds & Flowers. There I contrast the classical Most Effective Pollinator Principle with the equally valid (but much less well studied) Least Effective Pollinator Principle, with a segue into one of my favourite tracks from Led Zeppelin’s second album: What is and What Should Never Be.
But back to the real subject of this post – a flower that corresponds to the classical bird pollination syndrome BUT is also pollinated by bees and (very surprisingly) wind! It’s such an interesting paper by Brazilian ecologists Amanda Pacheco, Pedro Bergamo & Leandro Freitas – here’s the reference and a link to the study:
For over 100 years the classical pollination syndromes have acted as a framework for understanding the ecology and evolution of plant-pollinator interactions. But we’ve long known that while they can be a useful shorthand, they do not fully reflect the complexity of how pollination systems evolve. That shouldn’t surprise us because, as I point out in my two recent books, we have data (of any quality) on no more than 10% of the 350,000 or so species of flowering plants!
In addition, those plants for which we do have good data are NOT a random subset of the flowering plants: they have been specifically chosen by researchers because they look to be good systems with which to address particular ecological or evolutionary questions.
Which is fine, but we MUST recognise that this imposes significant restrictions on our understanding of the biodiversity of plant-pollinator interactions. The authors of this paper expressed it very well when they wrote that assumptions about:
“predictability may cause researchers to take for granted that only birds pollinate ornithophilous flowers, hindering research on the contribution of other vectors.”
To which I’d add: it also hinders our understanding of how these interactions evolve over long time scales and across multiple populations.
An obvious question is: how frequent are these sorts of complex pollination systems, involving different pollen vectors of an apparently specialised flower? The answer is that we simply don’t know, because most researchers would have not gone into this level of detail. So a huge congratulations to the authors for a great study – I hope it stimulates others to look beyond the ‘expected’ pollinators of flowers.
Photos: Nathália Susin Streher from the original paper.
Prof. Jeff Ollerton - ecological scientist and author 