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Heather aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution:
Aphis callunae is a small rather stout dark brown aphid which appears pinkish because of the powdering of wax. Blackman describes immature Aphis callunae as 'greenish' in life, but we have found them to be reddish brown (see below). The dorsal cuticle is strongly reticulate. The abdominal tergites are usually only banded on tergites 7-8. The siphunculi are very short, only 0.64-0.79 times the length of the cauda. The body length of Aphis callunae apterae is about 1.7 times the body width (in live specimens), with an absolute body length of 1.0-1.4 mm.
The images below show a winged, and a wingless, Aphis callunae in alcohol.
The heather aphid does not host alternate. Sexual forms occur in autumn. Aphis callunae feeds on heather (Calluna vulgaris) and is reported to live on old straggling plants typical of woodland clearings and margins. Aphis callunae is found over much of western, northern & central Europe, and has also been recorded from Canada.
Biology & Ecology:
Despite the superabundance of its foodplant - heather - in many areas, Aphis callunae is not usually a common species. Stroyan (1984) suggests that this aphid is overlooked and under-recorded, partly because of its very cryptic appearance and partly because it shows thanatosis (feigning death) when beaten from vegetation. This is certainly the case, but ant-attended colonies are very easy to find, so we suspect the aphid is genuinely rather uncommon. In the northern parts of its range its life cycle is apparently reduced to three generations (Stekoshchikov & Buga, 2009).
The heather aphid is tended by a number of different ant species including Myrmica sp. (see first picture below) and Formica rufa (see second picture below).
Brian et al. (1965) note that Lasius niger in British heathland obtains a great deal of food in exudates from various aphid sources including Aphis callunae on Calluna vulgaris. We have found that southern wood ants abandon colonies of heather aphids very quickly if disturbed. In other words no serious attempts are made to defend the aphids, unlike for example when wood ants are attending Symydobius oblongus. Indeed, the ant in the image above made no attempt to remove the syrphid larva from the aphid colony, despite its obvious predations on the colony.
Apart from syrphid larvae, we have also observed adult eyed-ladybirds (Anatis ocellata) close to colonies. This is a species normally associated with pine trees, which frequently grow in Calluna heathland.
Other aphids on same host:
Blackman & Eastop list 3 species of aphid as feeding on heather (Calluna vulgaris) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists all 3 as occurring in Britain (Show British list).