slow down and smell the … rotting flesh?

by Kate Freeman

Spring has announced its arrival — the generous daylight and boisterous birdsong have made it abundantly clear. It feels positively trite to write a piece about springtime wildflowers, but I really can’t help myself, so bear with me. On a recent hike out on the land, I was treated to views of several spring ephemeral flowers. These blooms caught my attention not only for their beauty, but also for their less than conventional breeding strategies. In this season of birds and the bees, I got to thinking about the innumerable pollination strategies that exist right in our own backyards. Some plants play nice, offering nectar rewards to incoming pollinators, but others use fraud and imprisonment to ensure pollination.  And while the birds and bees get plenty of credit, the less glorified creatures on which our native flora rely for propagation deserve some consideration. Here is my ode to the flies, mosquitoes, spiders and beetles, as well as the devious floral sirens that attract them. 
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What first got my mind in the gutter — or leaf litter — was the sight of this gorgeous native fairy slipper orchid, Calypso bulbosa. The unique morphology of these little stunners is comprised of petals and sepals suspended above a large, modified petal. This lower petal creates a slipper-shaped pouch, thus, the namesake fairy slipper. 

Fairy slipper Orchid

Orchids, who are specialists at being weird, are skilled at the art of deception. Many orchids use trickery to attract pollinators. They advertise food without ever producing any, or they mimic female insects to lure in breeding males. C. bulbosa attract pollinators via food deception: Despite being nectarless, they have a sweet odor and lure in hungry insects with small hairs inside the pouch resembling nectaries. The pollen is packaged on sticky disk-shaped structures near the entrance of the pouch. When unsuspecting bumblebees (Bombus species) enter C. bulbosa flowers, pollen is drawn to their large thorax, much like dog hair to your favorite sweater. After an unsated withdrawal, bumblebees spread pollen to neighboring orchids.

Checker lily

As I moseyed along a riparian (Creekside) trail, a small patch of checker lilies, Fritillaria affinis, caught my eye. The checker lily, native to western North America, is also known as mission bells, chocolate lily and riceroot. The latter pseudonym describes the bulbs from which these flowers grow, which resemble a small mass of rice grains. Apparently, native coastal tribes ate checker lily stems and bulbs, either roasted or steamed in pits.  
 
While lilies are often associated with pleasant odor, I wouldn’t advise sticking your nose into every flower of this tribe. Several members of the Fritillaria genus mimic the smell of dead animals or dung to attract fly pollinators. The strategy of attracting carrion-dwelling flies is known as sapromyophily. These plants emit a rancid odor, are usually brown or orange, and often have mechanisms to trap pollinators without providing a nectar reward. 

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My walk through this shaded rich woodland provided one last treat: the understated yet beautiful Trillium ovatum (Pacific or Western trillium). I remember being enchanted by the scarlet-colored Stinking Benjamin trilliums in the forests of my New England childhood, so this was a particularly nostalgic encounter. Trilliums are another black sheep of the pollination world, using fetid olfactory cues to attract flies and beetles. T. ovatum, with a large and open flower structure, white color and lack of nectar are likely adapted for pollination by beetles. Sap beetles (Nitidulidae), rove beetles (Staphylinidae) and flower long-horned beetles (Lepturniae) are frequently observed carrying T. ovatum pollen.
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I’m not suggesting we all go around patting dung flies on the back or blowing beetles tiny kisses. But maybe the next time you pick up that fly-swatter, take a moment to appreciate that the fly may have contributed to the vibrant floral tapestry that surrounds us.

Trilliuam ovatum

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Kate Freeman is stewardship assistant project manager for Sonoma Land Trust.

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