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Snowberry aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Aphthargelia symphoricarpi (see first picture below) are black or dusky green (cf. Aphthargelia rumbleboredomia, which has red/orange coloration on the dorsum, especially around the siphunculi and laterally). There are variably developed powdery white wax bands on the head, thorax and abdominal tergites. The most common form is cross bands on abdominal tergites I, IV, V and VIII, but they vary from being almost entirely black, to having to cross bands on all tergites (for the latter see second picture below). There is also a partial or complete spinal wax band from the cauda to the prothorax, where it is broadest, as well as marginal wax bands. The antennae have segments I and VI dark, segment II dusky, segments III-IV pale, and segment V pale with a dark apex. The antennal tubercles are moderately prominent, distinctly exceeding the middle of the frons. The rostrum extends almost to the hind coxae. The prothorax has marginal tubercles, sometimes very large and/or split into two separate tubercles. The abdominal dorsum has a large dark reticulated shield and/or bands on all terga, sometimes narrowed on abdominal tergum II and/or broken in the middle on posterior segments (cf. Aphthargelia rumbleboredomia, which has much reduced dorsal pigmentation on tergites V-VII). Strong marginal tubercles are present on abdominal segments II-V and immediately anterior to the siphunculi. The appendages are mostly pale, the siphunculi and anal plate are black and the cauda is dusky. The siphunculi are imbricated, and often slightly swollen. The cauda is more or less triangular, with 6-19 hairs (rarely less than 10).
Note: Aphis symphoricarpi Thomas, Aphis albipes Oestlund and Brevicoryne symphoricarpi, Gillette and Palmer are all synonyms for Aphthargelia symphoricarpi.
First image above copyright Andrew Jensen, second image copyright Jason Headley,
The alate (not pictured) has most of the body, legs, and antennae dark bluish-grey, usually without wax. The abdominal tergum has dark lateral sclerites, intersegmental muscle attachment plates, and various blotches or bands on tergites II-VIII. Between the siphunculi there is a transverse band connected to sclerites surrounding bases of siphunculi and about equal in thickness to the bands/blotches on tergites II-IV. The siphunculi are dark, The cauda is more or less triangular, with 12-20 hairs. Immature apterae & alatae (see picture below) are red-brown (this is not mentioned in most descriptions, but is given in Oestlund, 1887 - as Aphis albipes).
First image above copyright Lynnette Elliott, second image CBG group,
Aphthargelia symphoricarpi feeds on the twigs of snowberry, especially Western snowberry (Symphoricarpos occidentalis) and round-leaved snowberry (Symphoricarpos rotundifolia). Feeding by the aphids results in curling of the leaves. The species is monoecious holocyclic, although males may appear throughout the life cycle (see Jensen in aphidtrek) - this phenomenon is observed in some other species, such as Nasonovia cynosbati. Aphthargelia symphoricarpi is found in western and central USA and Canada.
Other aphids on the same host
Aphthargelia symphoricarpi has been recorded on 7 snowberry species (Symphoricarpos albus, Symphoricarpos albus var pauciflorus, Symphoricarpos occidentalis, Symphoricarpos orbiculatus, Symphoricarpos oreophilus, Symphoricarpos rotundifolius var parishi, Symphoricarpos symphoricarpos).
Blackman & Eastop list 11 species of aphid as feeding on snowberry (Symphoricarpos albus worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 6 as occurring in Britain (Show British list).