Genus Euceraphis [Calaphidini]
Rather large active but fragile aphids with long thin legs. All adults apart from oviparae are winged insects. They secrete a bluish white wax, often in the form of tufts on their legs. The antennae are usually longer than the body. The birch-feeding species may have black dorsal abdominal markings. The cauda is knobbed and the anal plate is rounded. The oviparae are large, apterous, yellowish to dark brown with dark dorsal abdominal markings, and with the posterior abdominal segments extended into an ovipositor-like structure.
A genus of 6 or more species living on the young shoots or the underside of birch and alder (Betulaceae). Adults may be found as accidentals on many plants besides their true hosts. They have a sexual stage in their life cycle, but do not host alternate and are not attended by ants. One species is considered a pest of ornamental birch varieties.
Euceraphis betulae (Silver birch aphid)
Immatures are green with conspicuous short black-tipped siphunculi. Adult winged viviparae have a pale green to pale yellow abdomen and are covered with bluish-white wax. The head and thorax of alates are black above and below and the legs and antennae are usually quite dark. Note that recently moulted specimens may be pale and lack wax. The dorsal abdomen may be unmarked, or have transverse black bands (common in spring and autumn) or black patches on abdominal tergites 4 and 5. The presence of dark cross bands in spring distinguishes specimens from Euceraphis punctipennis. The body length of alates is 3.0-4.2 mm.
The silver birch aphid lives on the undersides of leaves of silver birch (Betula pendula). Sexual forms occur from September to November. It occurs throughout Europe and has been introduced to North America and Australia.
Euceraphis punctipennis (Downy birch aphid)
Adult winged forms have a pale green abdomen and are covered with bluish-white wax. The head and thorax are dark brown. Dorsal black patches when present are usually confined to abdominal tergites 4 and 5. Dark cross bands are never present in spring (distinguishes specimens from Euceraphis betulae, at least in spring!). The body length of alates is 3.0-4.8 mm.
The downy birch aphid lives on the undersides of leaves of downy birch (Betula pubescens). Sexual forms occur in October and November. It occurs throughout Europe.
- Stroyan, H.L.G. (1977). Homoptera: Aphidoidea (Part) - Chaitophoridae and Callaphidae. Handbooks for the identification of British insects. 2 (4a) Royal Entomological Society of London. Full text
David Fenwick, 22 August 2013, Euceraphis
Wondered what you thought of this Euceraphis, was on Silver Birch but there was Downy all around too. I'm thinking possibly Euceraphis punctipennis.
Goss Moor, Mid-Cornwall. 21.08.13.
Images copyright www.aphotofauna.com all rights reserved.
With black bands on abdominal segments IV & V, these could be either Euceraphis betulae or E. punctipennis.
In the autumn the only way to tell the difference between these 2 species is to examine the ratio of the length of the base of the 6th antennal segment VI, to the length of 2nd hind tarsal segment. This ratio is larger in E. punctipennis than E. betulae.
Unfortunately these photos really don't have enough detail for such measurements.
Sally Luker 19/10/2014
I'm in the process of sorting data from this year's fieldwork, and today is aphid ID time. Attached are a couple of pics of aphids found on an ornamental birch in Morrab Gardens, Penzance. Although the aphids look very familiar, I'm struggling to come up with an ID for them - it's probably really obvious but any help would be much appreciated!
Images copyright Sally Luker, all rights reserved.
Sally Luker 19/10/2014
I'm happy with Euceraphis sp. (I talked myself out of even getting to that stage!). Thanks for the ID advice also. Right, back to the remaining mysteries...