This week on the Local Food Report, the return of a bee that’s co-evolved with American chestnut trees.
For years now, I’ve been researching tree crops. Which are the most productive, what they need, and how they fit into our local ecosystems and cuisines. I’ve spent a lot of time talking to people about chestnuts and chestnut trees. But until the other day, I’d never heard of the chestnut mining bee. Here’s Hannah Pilkey, a researcher with the SUNY College of Environmental Science and Forestry in New York State.
Hannah: It's a really cute bee, I'll say, right off the bat. It's really small, kind of not very flashy. You probably wouldn't even know you were seeing it when it's around.
I saw some pictures, and to my very untrained eye, it looks kind of like a tiny honeybee. Not an insect that would jump out at you—unless you were looking—and most researchers haven’t been, because for decades now, the chestnut bee has been thought to be extinct.
Hannah: But in 2018, it was rediscovered on an Allegheny chinkapin, which is kind of like a cousin of the American chestnut. It's in the same genus, Castanea. So that was kind of like renewed the interest that, okay, they previously thought that this bee was extinct when the chestnut blight came in and so many of them died, this was kind of one of the insect species that they thought, you know, so reliant on chestnut, there's no way it could still be around or it hasn't been recorded. And so when it was found again, that was the renewed interest in searching for this bee.
Hannah’s colleague Molly Jacobson was the first to find the chestnut mining bee, or “Andrena rehni” in New York since 1904 when she noticed it visiting a SUNY research orchard in 2023. And this rediscovery has opened up all kinds of new questions about the bee.
Hannah: It's a solitary bee compared to like, when you think of like a bumblebee or a honeybee, which creates hives. This is just a tiny little bee. It lives in the ground, just makes the few young. There's no queen. And so it's hard to hard to study this bee. But there have been a lot of entomologists recently that are trying to rediscover it and see where it still lives, where it's been hiding all these years.
A lot of insects are specialists—they feed on only the plants of one genus, or even one species. This is why our global mixing of plants has wreaked such havoc on the insect world over the last few hundred years—and why so many farmers and gardeners are starting to think about what they’re planting through this lens. It’s not just about pollination. We need a diversity of insects and healthy populations to have functioning ecosystems—which is why it’s so exciting to see the chestnut mining bee living on, even after the near extinction of its most important host tree. Now researchers are beginning to study whether the bee can only feed on native plants in the chestnut family, or if it’s also been relying for survival on non-native chestnut species.
Hannah: When the chestnut bee was originally found, it was on, it's still a North American species, the Allegheny chinkapin, so that shows that, you know, they're not just going to be feeding on Castanea dentata, the American chestnut, you know that seems like they'll shift a little where they need to. So, if I had to make an educated guess, I would think that they would also be on the Asiatic species as well, or the European chestnut, but more research is needed.
This is important, because a growing number of farmers are planting these non-native chestnut trees for food production. And while we know that American chestnuts were once an incredibly important plant species for insects, we don’t yet know how native chestnut loving insects respond to hybrid or non-native or even blight tolerant transgenic American chestnut trees —which is what Hannah is working to breed at SUNY.
Hannah: People, they're very interested in getting blight tolerant trees. And so a lot of people are like, well, what's the point of getting a wild type American chestnut tree that's non-transgenic? I don't want one of those. And I think this is a great example, is that it's still really important, even if the tree will eventually succumb to blight. You know, this is just one way, you know, planting our native species will help our native insects too, which is incredible.
Until we’re able to restore the American chestnut, it’s kind of like helping these insects tread water.
