#3678 - Tuberculatus annulatus - Oak Aphid
Infesting some roadside Quercus.
Originally Aphis annulatus, named as such by German forest biologist Theodor Hartig in 1941. Subsequently wandered through Callipterus, Callipterinella, Myzocallis and Tuberculoides until it settled in Tuberculatus, a genus coined in 1894 by Russian entomologist and parasitologist Aleksandr Mordvilko. The tubercules in question are bumps on the upper surface on the abdomen of adult females. I'm not sure where the rings referenced by 'annulatus' are.
The Oak Aphid is most often found in Europe, but iNaturalist has records in North America, Australia and New Zealand. Apparently they were more abundant in Australia before the devestating heatwaves of 2020, but given how rapidly aphid numbers can explode, they've probably recovered by now.
Aphids of this genus feed on trees from the family Fagaceae - beeches, chestnuts, and oaks. Since many aphids are vectors of plant disease, their symbiotic relationships with bacteria and ants has been closely studied. One study, for example, found differences in which endosymbiotic bacteria the Oak Aphids had depending on whether they lived in naturally regrown or artificially regenerated oak forest.
Christchurch, NZ.
