Last week while conducting a natural resource inventory on Swan’s Island, off the coast of Maine, I got to explore a nice big bog. It had no pitcher plants or leatherleaf, which are plants I normally think of as being prominent in a bog community. Instead it was largely covered with huckleberry, with scattered spruce and tamarack saplings. Some of the most abundant herbaceous plants were graminoids (grasslike plants). The whole place was dotted with white tufts of tawny cottongrass (Eriophorum virginicum), some of which are visible in the lower left of the above photo. Don’t let the name fool you; it’s actually a sedge. A less showy, but equally (if not more) abundant, plant there was white beakrush (Rhynchospora alba). Don’t let the name fool you; this, too, is actually a sedge. Here and there, there was some Canada rush (Juncus canadensis), which is in fact a rush. Among the Canada rushes were some much larger inflorescences, reminiscent of those of certain sedges, yet these were not sedges: I’m not sure what I would have thought these were, had I not perused Johnson’s List of the Insect Fauna of Nantucket* last fall to learn what gallmakers and leafminers were already known from the islands of Nantucket and Tuckernuck in preparation for surveying for these things there. In the entry for Livia maculipennis (Liviidae; listed by Johnson under Chermidae) was this note: “The nymphs develop in a gall formed on rush (Juncus).” Curious what a gall on a rush would look like, I had investigated a bit and found this paper**, which illustrates the gall in which this psyllid develops. (A psyllid is a member of the superfamily Psylloidea. Psyllids are sometimes called “jumping plant lice,” “plant lice” being an old name for aphids.) The structures I found in Maine seemed like a good match, so I broke off a chunk of one and pried open one of the florets, and sure enough I found a psyllid nymph inside:
I took that chunk of the gall home with me to get those photos, so I figured I might as well hang onto it to see if I got any adults. Sure enough, a few days later there were three adults crawling around in the vial, along with two nymphs.
I haven’t looked for a description or illustration of L. maculipennis, but given that “maculipennis” means “spotted wing,” it seems reasonable that it would look like this.
If you have an eye for tiny things, you may have noticed that there are several psyllids visible in my photo of the gall. I sure didn’t notice them at the time; I was in a hurry since I had to finish inventorying a whole ~80-acre property in time to catch the ferry back to Bass Harbor. These psyllids have clear wings and plain orange bodies. I suspect that they are the same species and are just teneral–that is, they haven’t developed their adult coloration because they have just recently climbed out of their nymphal skins.
Added 6/14/2015: In the comments below, Chris Mallory pointed out that the species I’ve illustrated here is in fact Livia bifasciata, which has been confused with L. maculipennis in older literature. The true L. maculipennis feeds on Juncus acuminatus rather than J. canadensis***.
* Johnson, Charles Williston. 1930. A List of the Insect Fauna of Nantucket, Massachusetts. Publications of the Nantucket Maria Mitchell Association Vol III, No. 2.
** Patch, Edith M. 1916. A Psyllid Gall on Juncus (Livia Maculipennis Fitch). Psyche 23(1):21-22.
*** Hodkinson I. D. & Bird J. 2000. Sedge and rush-feeding psyllids of the subfamily
Liviinae (Insecta: Hemiptera: Psylloidea): a review. Zoological Journal of the Linnean Society 128(1):1-49.