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Redbud aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Aphis pawneepae have the head and thorax brown, and the remaining body portion reddish-brown, with a fine covering of white wax powder (but see note below). The antennae are dusky-brown; the base of the third segment is lightest and apical antennal segments progressively darker. The legs are brown with knees and apical portions of femora and tarsi dusky. The siphunculi and cauda are dark. The antennae are either five- or six-segmented. When six segmented, the antennal terminal process is about twice as long as the base of antennal segment VI (cf. Longistigma caryae, which has the terminal process shorter than the base of that segment). Secondary rhinaria are absent. The rostrum reaches mid-way between the meso- and meta-thoracic coxae. The prothorax has a pair of very large marginal tubercles. The siphunculi are rather short, poorly imbricated without a flange, taper slightly towards the apex, and about 1.3 times the caudal length. The cauda is more or less triangular, with about 20 hairs. The body length of adult Aphis pawneepae apterae is 1.5-1.7 mm.
Note: No mention was made in the original description by Hottes (1934) of any wax powdering on the live insect. This may be because the Aphis pawneepae he found were in earth shelters (='sheds', or 'tents') constructed by Crematogaster ants at the ground surface around seedlings. When ant-tended, at least some aphid some species loose the wax covering, or possibly do not secrete much wax, see Cinara costata.
Image above copyright Even Dankowicz, under a Creative Commons Attribution License.
Alate Aphis pawneepae have the head and thorax dark dusky brown to black, and the abdomen with lateral patches (marginal sclerites ?) of darker brown. The wing veins are dark brown and bordered with fuscous. Alatae have 2-5 (usually only 2) secondary rhinaria on the basal part of antennal segment III.
Aphis pawneepae is monoecious holocyclic on redbud (Cercis canadensis). Parker (1935) found colonies arranged along the undersides of twigs and branches, always on old wood, much as shown in the picture above. Hottes (1934), however, found them in ant shelters constructed by Crematogaster lineolata, just at the ground surface, encircling the trunks of small seedling trees. The only exception to this was the fundatrices which were on stems of the host plant. The redbud aphid has been found in Illinois, Kansas, Montana, North Carolina and Pennsylvania, USA.
Other aphids on the same host
Aphis pawneepae has been recorded from 1 species of red bud (Cercis canadensis).
Blackman & Eastop list 2 species of aphid as feeding on red bud (Cercis canadensis) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists none as occurring in Britain (Show British list).