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Long-legged serviceberry aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Acyrthosiphon macrosiphum have an amber-yellow head and the rest of the dorsum yellow-green to green (the picture below shows a fundatrix, which appears to be more yellowish than the apterous vivipara). Antennal segments I to the middle of III are pale, but the distal segments are dusky to blackish. The rostrum reaches the second coxae. The apical rostral segment (RIV+V) is shorter than the length of the second hind tarsal segment. The tibiae are light brown, darker at knees and tips. The siphunculi have a broad base, but narrow rapidly to become more or less cylindrical; they are without reticulation. The siphunculi are very long, longer than antennal segment III, and about twice the length of antennal segment IV. The cauda and anal plate are pale. The cauda is parallel-sided to tapering, and bears two lateral pairs of hairs and 3-4 dorsal or dorsolateral hairs. The body length of adult Acyrthosiphon macrosiphum apterae is 1.5-1.9 mm.
Image above copyright Andrew Jensen under a Creative Commons License.
The alate vivipara (not pictured) of Acyrthosiphon macrosiphum is similar to the apterous vivipara, but with a brownish head and thorax. The abdomen is yellow green. The rostrum hardly reaches the second coxae. The siphunculi are pale to light dusky, without reticulation. There are 19-44 secondary rhinaria on antennal segment III.
Images above copyright CBG Photography Group under a Creative Commons License.
Acyrthosiphon macrosiphum is monoecious, feeding on the leaves of serviceberry (Amelanchier spp.) and possibly American elder (Sambucus canadensis). The species is found on different Amelanchier species in a range of habitats from moist forests to riparian habitats to deserts. Jensen, in aphidtrek, notes that in desert this species has a quite different appearance with lateral green stripes on the head and thorax, albeit there were no obvious morphological differences between desert- and forest-inhabiting populations. Acyrthosiphon macrosiphum is holocyclic, with sexuales recorded in September and October. It seems to be restricted to the western states of the USA (California, Colorado, Utah, Oregon, Montana) and western Canada (British Columbia, Saskatchewan).
Other aphids on the same host
Acyrthosiphon macrosiphum has been recorded on 4 species of serviceberry (Amelanchier) (Amelanchier alnifolia, Amelanchier florida, Amelanchier laevis, Amelanchier utahensis).