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Aphidinae : Uroleucon nigrotibium
 

 

Uroleucon nigrotibium

Dark-legged goldenrod aphid

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

Identification & Distribution

Adult apterae of Uroleucon nigrotibium have the entire body red-brown (cf. Uroleucon cadens, Uroleucon caligatum, Uroleucon erigeronense and Uroleucon gravicorne, which have the body green). Their antennae are mainly dark with 7-16 secondary rhinaria on antennal segment III (cf. Uroleucon atripes, which has 13-47 secondary rhinaria on that segment). Marginal sclerites are dusky and broken, and scleroites are dusky and larger than those of alate viviparae. The second hind tarsal segment (HTII) is shorter than the apical rostral segment (RIV+V), and shorter than antennal segment I. The legs have the proximal half of the femora pale, and the distal half dark dusky to dark. The tibiae are almost uniformly dark (cf. Uroleucon solidaginis, which has tibiae with a pale section in the middle). The first hind tarsal segment (HTI) has 3 hairs (cf. Uroleucon atripes, which usually has 5 hairs on HT I). Abdominal tergite VIII usually has 2 hairs (cf. Uroleucon atripes, which usually has 4 hairs on abdominal tergite VIII). The siphunculi are entirely dark and the cauda is pale.

Both images above by permission, copyright Claude Pilon, all rights reserved.

Alate Uroleucon nigrotibium viviparae are similarly coloured to the apterae. They have 14-39 secondary rhinaria on antennal segment III. There are dusky marginal sclerites on abdominal segments II, III, and IV, all bearing small transparent marginal tubercles. The antesiphuncular sclerites are broken, but postsiphuncular sclerites are large and entire.

The images below show (first) a colony of Uroleucon nigrotibium on its host plant, and (second) a clarified mount of an alate Uroleucon nigrotibium.

First image above by permission, copyright Claude Pilon, all rights reserved
Second image above copyright CBG Photography Group under a Creative Commons license.

Uroleucon nigrotibium appears to be restricted to a few species of goldenrod, especially grey goldenrod (Solidago nemoralis) and sweet goldenrod (Solidago odora). These aphids fall readily from their host when disturbed, much like Uroleucon cadens and Uroleucon crepusisiphon. All three species produce few winged morphs, but apterae walk frequently between plants, thus initiating new colonies nearby (Moran, 1985). The species is known from the eastern states of the USA (Michigan, North Carolina) and from Canada (Quebec).

 

Other aphids on the same host

Uroleucon nigrotibium has been recorded on 2 or possibly 3 species of goldenrod (Solidago nemoralis, Solidago odora, ?Solidago microglossa).

Acknowledgements

We are grateful to Claude Pilon for pictures of Uroleucon nigrotibium (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 accounts of Olive (1963) (as Dactynotus nigrotibius) and Moran (1985), and noted Richards (1982) (as Dactynotus nigrotibius), 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

  • Moran, N. (1985)[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. Abstract

  • Olive, A.T. (1963). The Genus Dactynotus Rafinesque in North Carolina (Homoptera: Aphidae). Misc. Publ. Entomol. Soc. Amer. 4, 31-66.

  • Richards, W.R. (1972). Review of the Solidago-inhabiting aphids in Canada with descriptions of three new species. The Canadian Entomologist 104(1), 1-34. Abstract