Back in May, while skittering down a slope of trachyandesitic scree near Travertine Hot Springs, I encountered a Utah juniper (Juniperus osteosperma) with anomalous growths at the ends of a few branchlets. Having recently read up on some galls on oaks at Grover Hot Springs, and galls on sagebrush beside the East Walker River, I thought another wasp or midge might be at work here.
Who did this? Sources I’ve found on the internet suggest it’s a still undescribed species of Juniper gall midge (Walshomyia sp.). See CalPhotos for another image (and another). Gall midges are tiny flies (Order Diptera) in the family Cecidomyiidae, subfamily Cecidomyiinae. Walshomyia includes the Juniper urn gall midge (W. juniperina), whose gall I’ve seen on a juniper at Grover Hot Springs, and the Cypress gall midge (W. cupressi).
At a glance, I can’t tell if these galls are developing on the apical buds of branchlets or on the young seed cones of these trees (normal growth shown below).
Below: Juniper gall midge habitat on a hill between Travertine Hot Springs and Bridgeport Valley. Buckeye Canyon and Flatiron Ridge in the background.
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Another option for the gallmaker might be Oligotrophus betheli. The difference between the two midges is driving me nuts. More details here in case of interest: https://www.inaturalist.org/observations/49430483.
Hi, Colin — Thanks very much for the additional info and links! It’s interesting to look closely at these galls, but quite a challenge to find definitive or detailed information on many of them.
Apparently all the pics of Oligotrophus betheli on iNaturalist are misidentified. You definitely have Walshomyia “sp. A” per Russo’s book on galls.