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Aphidinae : Uroleucon russellae
 

 

Uroleucon russellae

Pearly everlasting aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult apterae of Uroleucon russellae are bronzy black with dark antennae. The antennal terminal process is about 4.5-6 times as long as the base of antennal segment VI. The apical rostral segment (RIV+V) is 1.8-2.3 times the length of the second hind tarsal segment (HTII) (cf. Uroleucon idahoensis, a pale green species also found on Anaphalis, which has RIV+V 0.8-1.7 times HTII). The dorsal abdomen has some hairs arising from dark scleroites. Antesiphuncular sclerites are totally absent, postsiphuncular sclerites are well developed. The coxae and the basal half of the femora are pale, the distal half of the femora is blackish. The distal half and the very base of the tibiae are black, with the basal half from brownish yellow to blackish brown. The siphunculi are black and reticulated over the distal 0.15-0.37. The cauda is usually darkish, sometimes almost black, and bears 12-23 hairs. The body length of adult Uroleucon russellae apterae is 2.5-3.3 mm.

Images above by permission, copyright Claude Pilon, all rights reserved.

The alate Uroleucon russellae is much like the aptera, but has the head and thorax blackish brown sclerotic. Antennal segment III has about 35-57 secondary rhinaria over very nearly its wholelength. The abdomen has dark marginal sclerites, and there is a more or less complete sclerotic band across tergite VIII. The siphunculi are less enlarged at base and thinner throughout than on the aptera, with the distal 0.2-0.67 reticulated. The wings have rather pale brownish veins.

Image above by permission, copyright Claude Pilon, all rights reserved.

Uroleucon russellae is found on the stems and leaves, and in inflorescences, of pearly everlasting (Anaphalis margaritacea) and catsfoot (Antennaria neodioica). Moran (1985) notes that the aphid's unusually long apical rostral segment is most likely an adaptation to the hairiness of its host. Sexuales develop in autumn with alate males, and the species overwinters in the egg stage. Hille Ris Lambers (1960) notes this species is rather common in Eastern Canada in the inflorescences of Anaphalis margaritacea. Similarly Jensen, in AphidTrek, notes that it is one of the few native Uroleucon species that is somewhat common in western North America. Uroleucon russellae is widespread in western and northern USA and across Canada.

 

Other aphids on the same host

Uroleucon russellae has been recorded from just 1 species of Anaphalis (Anaphalis margaritaceae).

Uroleucon russellae has been recorded from just 1 species of Antennaria (Antennaria neodioica).

Uroleucon russellae is also the only aphid recorded from Helichrysum virgineum (in British Columbia, but whose native range is Central Lebanon) and has been found on 3 Gnaphalium species in California, see Blackman & Eastop Aphids on Worlds Plants.

Note: Anaphalis, Antennaria, Helichrysum and Gnaphalium are closely releated, often synonomized, genera within tribe Gnaphalieae of family Asteraceae.

Acknowledgements

We are grateful to Claude Pilon for pictures of Uroleucon russellae (for more of her excellent pictures see).

Identification of specimens photographed by Claude Pilon was confirmed by Eric Maw by microscopic examination and DNA analysis of preserved specimens. For taxonomic details we have used the account of Hille Ris Lambers (1960) and Moran (1985) together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

Useful weblinks

References

  • Hille Ris Lambers, (1960). Some new genera and species of aphids from Canada (Homoptera: Aphididae). The Canadian Entomologist 92(4), 251-265. Full text

  • Moran, N.A. (1984). The genus Uroleucon (Homoptera: Aphididae) in Michigan: Key, host records, biological notes, and descriptions of three new species. Journal of the Kansas Entomological Society 57(4), 596-616. Full text