Who Pollinates Michigan Lilies?

Bees do it, birds do it, perhaps even educated fleas do it – transport pollen, that is. All of us are aware of the pollinating activities of bees and some of us know that hummingbirds pollinate gorgeous wetland plants called cardinal flowers. The cardinal flower blossoms are artfully designed to dust a hummingbird’s head with pollen as it sups nectar.

Michigan lily. Photo by Bob Noble.

Lily interior. When sipping nectar the butterfly wings can’t help but rub against the anthers and pick up pollen. Photo by Bob Noble.

Lily pollen is copious and sticky. Photo by Bob Noble.

Michigan lily close up showing anthers loaded with pollen and stigma (female flower part) in centre. Photo by Bob Noble.

Ah, but who pollinates Michigan lilies? Their vibrant orange flowers are currently lighting up moist habitats in Headwaters. I also grow them in my garden and have watched and waited in vain for bees and other small buzzing insects to visit them. It’s like staking out a liquor store on Canada Day.

Enter the flame azalea, a wild rhododendron from the Appalachians. A recent discovery found that azalea pollen is transferred from flower to flower by the wings of tiger swallowtail butterflies.

The structure of the bright orange flame azalea flowers is key. The stamens and stigmas of the azalea flowers extend well beyond the petals.

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As swallowtails sip nectar, probing deep into the flowers with their long tongues, the stamens, capped by pollen-coated anthers, are perfectly placed to spangle the underside of the flapping butterfly wings with pollen.

The butterfly wings then deliver that pollen to the stigmas – the female reproductive organs – of other lilies.

It occurred to me that my Michigan lilies had precisely the same flower structure as flame azaleas. Could the answer to my pollination puzzle be butterfly wings? Maybe Michigan lilies don’t need bees, flies and wasps because they have their own bespoke pollinator.

Nectar droplets deep in flower, inaccessible to some bees, but not the long tongue of a butterfly. Photo by Bob Noble.

Tiger swallowtail wings fluttering, hence the blur but note pollen on underside of butterfly wings. Photo by Don Scallen.

Tiger swallowtail. Photo by Bob Noble.

Tiger swallowtail drinking the nectar of wild bergamot. Photo by Bob Noble.

And this year, a breakthrough. I watched as a tiger swallowtail visited the lilies in my yard, something that surely happens more frequently in wilder places with more butterflies.

That some flowers have evolved to deliver their pollen on butterfly wings is no great surprise. Nature’s genius provides myriad solutions to the challenge of transporting pollen.