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Common oleaster aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution:
Apterae in spring populations of Capitophorus elaeagni on the primary host are pale yellowish green (see first picture below). Their abdominal dorsum is reticulate or sculptured. Each of abdominal tergites I-IV usually have 2 spinal, 2 pleural and 2 marginal hairs (cf. Capitophorus similis which has 4 spinal, 4 pleural and 6 marginal hairs on each of tergites I- IV). The siphunculi are cylindrical or tapering and are dusky to dark right at the apices (cf. Capitophorus carduinus which has siphunculi which are not dark at the apices). The body length of wingless viviparae on the primary host is 1.9-2.5 mm. Wingless viviparae on the secondary host (various Compositae) (see second picture below) are greenish white to yellowish green with dark tips to the siphunculi. The body length of wingless viviparae on the secondary host is 1.4-2.5 mm.
Second image above copyright Mihajlo Tomić, all rights reserved
Winged viviparae produced on the primary host (see third picture above) have a black head and thorax, black antennae and a blackish dorsal abdominal patch.
Note: Blackman (2010) indicates that the sexual phase of Capitophorus elaeagni that occurs on Elaeagnus in continental Europe has not (till now) been recorded in Britain. However, the siphunculi are clearly dark-tipped which suggests our identification is correct.
The clarified slide mounts below are an adult viviparous female Capitophorus elaeagni : wingless and winged.
The common oleaster aphid host alternates from oleaster (Elaeagnus) or sea buckthorn (Hippophae) to various thistles and daises (Asteraceae). Sexuales are produced in the autumn, and the species overwinters as eggs on the primary host. Capitophorus elaeagni is found over most of the temperate, and warm temperate, parts of the world.
Other aphids on same host:
Capitophorus elaeagni has been recorded from 8 Elaeagnus species, and 1 Hippophae species (Hippophae rhamnoides =Elaeagnus rhamnoides, sea buckthorn).
Blackman & Eastop list 10 species of aphid as feeding on oleaster (Elaeagnus species) and/or sea buckthorns (Hippophae species) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 4 as occurring in Britain (Show British list).