A few weeks ago I wrote about a mystery plant from Arizona that I suspected was a mallow because of its leaf mines and the fly that had emerged from one of them. Among the few responses I got, there was a consensus that the plant was in fact a mallow, although there was disagreement about whether it was a Sphaeralcea (globemallow) or a Sida (most of which are known as fanpetals). After browsing through online photos, I believe the former is more likely. I wrote to Owen Lonsdale with this update to the specimen data, and he said that he has examined a confirmed Calycomyza malvae specimen from Arizona, so my suggested ID for this fly (otherwise only known from the eastern US) is entirely plausible. As to whether my specimen was consistent with females of this species, he said “it does largely agree with the females I’ve seen, being slightly more robust and setose [big and hairy] than most other” Calycomyza species, but as I noted before, a male is really needed to be sure of the species.
Since the host plant’s identity couldn’t entirely be nailed down, I’m not too upset that the fly couldn’t be identified to species either. But I reared two other leafminers from a mallow elsewhere in the Sonoran Desert, and since these insects can be identified to species, I am interested in figuring out for sure what plant they came from. It seems to be an Abutilon species; suggestions have included both A. incanum and A. parvulum, but I haven’t seen photos of either species that satisfy me completely.
The leaf to the right in the photo above has a mine of a Bucculatrix species. Most larvae in this moth genus start out making a linear leaf mine like this, then exit to feed externally, skeletonizing little patches of the leaf surface, as shown in the photo below.
A better look at the larva:
About a week after I collected it, the larva spun a ribbed cocoon as is typical of Bucculatrix species.
Two weeks after that, the adult moth emerged, sporting the usual Bucculatrix pom-pom on the forehead.
When I say this can be identified to species, maybe I’m just being optimistic. I haven’t yet sent it to a lepidopterist to examine, but with any luck it will conform well to something described in Annette Braun‘s 1963 revision of the genus. Several Bucculatrix species have been associated with mallows (Malvaceae), but none with the genus Abutilon, and the only one of these recorded from Arizona seems to specialize on cottons (Gossypium). I reared that one too, and it is obviously not the same species as this one.
The other miner I found on this plant, however, has already been examined by an expert and deposited in the Smithsonian. I only found a single example of the mine…
…but I lucked out and the adult beetle emerged nine days later:
Charles Staines identified this as Stenopodius texanus, a species that has not been reared before and has only been associated with Sphaeralcea species (globemallows).
It is because both these rearings seem to represent new host records that I am so interested in figuring out exactly what the host plant is. Those of you who read this post may remember me talking about this plant and its leafminers before. Since then I have realized that some of the plant photos I had associated with these insects depict another mallow species, Hibiscus denudatus. The confusion arose from the fact that the two photos below came immediately after the photo of the Bucculatrix larva above. However, after much puzzling and trying to sort out which leaves went with which plant, I finally noticed that although these photos were the next ones I took, they were actually taken a half hour later, along with a photo of an unmined leaf. So it seems safe to conclude that I reared both insects from what I’m calling Abutilon and found no mines on the Hibiscus.