Petal Power
Thoughts on a recent study on flowering plants, specifically pansies.
To make a prairie it takes a clover and one bee,
One clover, and a bee,
And revery.
The revery alone will do,
If bees are few.
― Emily Dickinson
You might need to change how you tell your kids about the birds and the bees, because, well, the bees are doing less of what they do, at least to flowering plants, which are responding to that by increasingly “selfing,” which, yes, is more or less what it sounds like, and about which I will say no more, this being a family publication.
I took a bit of liberty there. It isn’t so much that the bees have decided to stop helping flowers reproduce; it’s that there are lots fewer bees around to do the job. So some flowers are producing less nectar and growing smaller petals, which are less appealing to pollinators, and instead putting the energy they save into pollinating themselves.
That’s a gross oversimplification of a study described in, among other places, the New York Times and the Guardian. The study, using pansies, was conducted by scientists who wondered if and how flowers were responding to the fast and severe loss of bees and other pollinators of the past few decades because, well, humans. The study answered with the inevitable: sure enough, they were, and here’s how.
Scientists estimate that selfing has increased about 27 percent since the 1990s. Although there’s nothing inherently problematic about the reduced size of the petals per se (other than our own aesthetic enjoyment), this business of self-polluting does bring with it what you might call a Royal problem: too much inbreeding. Scientists speculate that with the loss of diversity in successive generations, flowering plants might be more susceptible to diseases and less able to adapt to future environmental changes. As to the nectar, well, as the populations of insects plummet—one study found a 75 percent drop in the weight of insects between 1989 and 2016, according to the above Guardian piece—those who rely on flowering plants for food will only decline faster. And all these adjustments have transpired over a mere 20 generations, blindingly fast in evolutionary terms.
I’ll skip over the guilt trip about the human role in this—I think most reasonable people are familiar with this trope by now—and close with one potentially positive sliver. Another study on morning glories in the southern states indicated that flowers had increased in size between 2003 and 2012—perhaps as a tactic to attract the few bees remaining.
A perfect excuse to link you to one of my favorite songs, by Mary Travers (of Peter, Paul, and Mary).
Lagniappe: Readers interested in reading about nature from a real naturalist (as opposed to an English major who used to go camping) should scurry over to fellow SubStack writer Bryan Pfeiffer’s magnificent newsletter Chasing Nature, where they will be rewarded with not only lovely, accessible words on all things bright and beautiful, but also jaw-dropping photos to go along with them.