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Identification & Distribution:Aphis taraxacicola apterae are mottled dark green (see first picture below), and (according to the literature) are not wax powdered.
Our photos, however, reveal that the dorsum of Aphis taraxacicola may be lightly wax powdered (see picture below). Their siphunculi are dark and the cauda is dusky. Aphis taraxacicola alates (second picture above) are also mottled dark green.
The terminal process of the sixth antennal segment is 2.1 to 2.8 times the length of the base of that segment. The abdominal sclerotic pattern varies from being heavily marked with dark intersegmental muscle sclerites and small marginal and postsiphuncular sclerites across tergites 7-8 to almost complete lack of any dark pigmentation. Abdominal marginal tubercles are rather large and prominent, and clearly visible in the micrographs below. Aphis taraxacicola siphunculi are 1.2 to 2.4 times the length of the cauda. The hairs on their legs are short with all femoral hairs shorter than the least width of the hind tibiae. The body length is 1.6 to 2.02 mm.
The dandelion aphid is found on the root collar and under the rosette leaves of Taraxacum (dandelion) species, mostly in dry sunny places with low or sparse vegetation. Aphis taraxacicola is usually ant attended and the ants tent over the colony with soil particles. It does not host alternate and sexual forms are found in autumn. Aphis taraxacicola is found throughout Britain and the rest of Europe and in Siberia, with additional records from Canada and Japan (Sugimoto & Takahashi, 1996 ).
Biology & Ecology:
We first came across the dandelion root aphid when walking along the road past a local churchyard. A dandelion (Taraxacum officinale) was (just) managing to grow between the wall and the tarmac, and had a powdering of soil over its basal rosette of leaves (see first picture below). Careful brushing away of the soil revealed a colony of mottled dark green aphids shown below. The aphids had been tented over with soil particles by common black garden ants Lasius niger (see second picture below), rendering the aphids themselves invisible to any casual observer.
Aphis taraxacicola is one of 14 aphid species recorded in the nests of Lasius flavus in Poland by Depa. & Wegierek (2011) It was found in a Lolio-Polygonetum meadow, situated in a housing estate, and described as intensively trodden on and regularly mown with a relatively low plant species diversity.
Despite this concealment and the attending ants, predators and parasitoids were still operating under the soil particle tent. We found parasitoids (below left, as yet unidentified) busy going round the colony parasitizing the aphids, and we found parasitized 'mummies' (below right). The straw-coloured aphid in the middle of this colony (second image on this page) was an aphid in process of mummification.
As for predators, attending ants can certainly reduce the number of predators, but we have still found syrphid larvae amongst Aphis taraxacicola colonies (see below).
Coccinellid larvae of the genus Scymnus are reputedly important predators of root aphids, but we have so far only found them predating conifer aphids and the pellitory-on-the-wall aphid (Aphis parietariae ).