I’ve now finished uploading plant photos from last fall’s road trip through the western states. If you’d like to help with identifying them, you can see them all organized by location here. Thanks to those who have helped out already; I’ve been moving photos of confidently identified plants to the “Identified” folder, so the other folders should be getting emptier and emptier.
Now comes the fun part in my photo sorting: matching my photos of leaf mines to my photos of insects that emerged from them. The plants from which I’ve reared adults are the ones I’m most interested in identifying, so that I can have complete data for specimen labels. Unfortunately, there are a few specimens that I’ve already sent off to specialists without knowing what the host plant was, so I’ll devote a couple of blog posts to trying to rectify this situation.
Here’s a shrub that was growing in the coastal chaparral of Monterey County, California. The leaves were no more than 15 mm or so long. Anyone recognize it?
The small leaf size did not dissuade leafminers from living inside them. Below is a leaf backlit to show the mine of a Stigmella species (Nepticulidae).
As I’ve probably mentioned before, the family Nepticulidae includes the smallest moths in the world, and as it happens, the day before I found these mines, I got to see this moth when I stopped by the Bohart Museum of Entomology at UC Davis. It was the smallest known moth at the time that article was written, but I was shown an even smaller one that had been found since then. Both looked like specks of dust to the naked eye.
Anyway, like most nepticulid larvae, these emerged from the mines before pupating. This one was about 2.7 mm long.
In the rearing vial, the larvae spun whitish cocoons on the undersides of the leaves. Most nepticulid cocoons I have seen have been a much darker brown.
On December 2 I found this moth in the vial, unfortunately already dead. It was 1.8 mm long.
I sent the moth to Erik J. van Nieukerken in the Netherlands, along with two larvae for DNA barcoding. On the same day I found the moth in the vial, I also found this parasitoid wasp, only 1.1 mm long:
I sent the wasp to eulophid specialist Christer Hansson in Sweden. He identified it as Chrysocharis wahli, which happens to be a species that he had named. Given the shortage of microhymenopterists in the world, it is a very unusual thing to have the name of a parasitoid before I know the name of its host or even the host plant. Chances are good that the moth doesn’t have a name yet anyway, but maybe someone out there has a name for the plant?
Added 10/14/2013: My tentative guess had been that the plant was some kind of Ceanothus, and several people have suggested this, but I am more convinced by the suggestion of Rhamnus crocea (redberry), or possibly R. ilicifolia (evergreen buckthorn). Everyone agrees that it is something in the buckthorn family (Rhamnaceae), making this the third time I have posted about a Stigmella species mining in a buckthorn: see also Rhamnus cathartica and Berchemia scandens. Thanks to everyone who chimed in!