Some flowers welcome birds more than bees.
Flowers have a knowing about how to evolve for their own best interests over time.
Take the glorious purple-belled common foxglove (Digitalis purpurea), for example.
The native European foxglove is pollinated by bumblebees.
Once foxgloves took root in the Americas, hummingbirds quickly fell in love with their nectar and became an important foxglove pollinator, so this pretty foreign transplanted flower has evolved due to pressure exerted by pollinating hummingbirds.
Evolutionary changes between plants and pollinators, like this one, can take place in 85 generations or less.
This unrelated 3:20-minute Botany with Brit video gives some good info on the foxglove:
At the University of Sussex in Brighton, UK, Maria Clara Castellanos along with her colleagues spent over 2,000 study periods of 3-minutes each tallying the pollinating visitors to foxgloves in Colombia, Costa Rica, and the United Kingdom.
Their findings indicate that hummingbirds pollinate up to 27% of the foxgloves in Costa Rica and Colombia where the corollas—the flowers’ long purple tubes that make them look so beautiful—are 26% and 13% longer, respectively, than the corollas of the British foxgloves.
Why would foxgloves develop longer corollas? And why do they do better? Survival, as always, is the bottom line.
Plants with corollas that are too long for bumblebees to reach the nectar, like some of those found in Central and South America, are guaranteed to be pollinated by hummingbirds. And hummingbirds are more effective than bumblebees at depositing the pollen on the next foxglove flower.
And just to sweeten the deal with hummingbirds even more, the longer corolla is a more comfortable fit for the hovering hummingbird, and this probably also improves pollination success rates.
Another factor is that the hummingbird has a farther flight reach, taking pollen a greater distance than a bee can. This can help reduce plant inbreeding, while it increases the range of pollination and therefore expansion in the environment.
Isn’t it fascinating to observe the intelligence of nature in action?
The foxglove is a very beautiful flower to behold… graceful and voluptuous, the abundant tubular blossoms dangle as an invitation to pollinators, but there is more to the foxglove than meets the eye.
It seems the foxglove is also as clever as a fox.