Although spring is technically already half over, it only really got started around here in the past week or so. Yesterday I saw my first spring beauties (Montiaceae: Claytonia caroliniana):
These little wildflowers are only around for a few weeks before they disappear along with their leaves, as do trout lilies, wild leeks, Dutchman’s breeches, and squirrelcorn. It’s striking how few of the spring wildflowers host any leafminers—not just these true “ephemerals,” but even many with persistent leaves: bloodroot, wild ginger, blue cohosh, early meadow rue, starflower, and goldthread are all entirely lacking in miners.
So I was excited to find some mines on spring beauty three years ago (May 17, 2015) during a walk in Marshfield, Vermont:
Here’s a backlit view of a different leaf, showing a larva feeding at the tip:
A look at the undersides of the leaves revealed tiny white eggs at the beginnings of the mines:
There are two eggs in the above photo, one of them unhatched. If you think they’re hard to spot, try finding them on a life-sized leaf! Here’s a closer view of a hatched one, next to a bit of pollen:
They were so tiny that I failed to recognize them as eggs of Pegomya (Anthomyiidae)—the genus that includes the flies that are already ovipositing in earnest on the spinach in our hoop house—and mistook them for Scaptomyza (Drosophilidae). As a result, after collecting them I didn’t provide the larvae with soil to burrow into, which is generally necessary when rearing anthomyiids. They began to pupate within two days, and although I had collected many larvae, I only ended up with one adult (on June 11):
As discussed in my paper on leaf-mining muscoid flies that was published earlier this year*, this was a female, and a male would be needed to identify the species with certainty. I sent it to Brad Sinclair at the Canadian National Collection and he said it might be Pegomya flavifrons, but he noted that it was dark compared with the much more yellow specimens of that species in the CNC. Pegomya flavifrons normally feeds on plants in the pink family (Caryophyllaceae). Here is one I reared from mouse-ear chickweed (Cerastium fontanum) in Maine:
Although this P. flavifrons is a darker gray, it does have a lot more yellow on its abdomen and face.
So this spring I’m hoping to find more larvae and rear some males to get a definite answer. However, I rarely encounter spring beauty where I live, and I have only seen mines on it that one time, so I’m hoping this post will inspire some of you to keep an eye out for them. If you find any larvae, please either try and raise them, or pass them along to me, or at least tell me where you found them!
* Eiseman, Charles S. 2018. New rearing records for muscoid leafminers (Diptera: Anthomyiidae, Scathophagidae) in the United States. Proceedings of the Entomological Society of Washington 120(1):25-50.