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Aphidinae : Uroleucon caligatum
 

 

Uroleucon caligatum =Uroleucon (Lambersius) caligatum

Northern green goldenrod aphid

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

Identification & Distribution

Adult apterae of Uroleucon caligatum are green with mostly-black antennae and legs. The siphunculi are also mostly black, but with pale bases, and the cauda is pale with a dusky tip. The antennal tubercles are well developed. The longest hairs on antennal segments III-VI are equal to the basal diameter of segment III. The apical rostral segment (RIV+V) is greater than 1.3 times the hind tarsal segment (HT II) (cf. Uroleucon tissoti, which has RIV+V less than 1.3 times HT II). Paired spinal tubercles are usually present on most or all of abdominal segments II-VII (cf. Uroleucon luteolum, which has no spinal tubercles present). Abdominal tergite VIII has 4 hairs. The second hind tarsal segment (HTII) is 0.125-0.17 mm, and longer than the maximum width of the hind femur. The siphunculi have a pale section at the base, and a distal zone of reticulation of at least 2-3 rows of closed polygonal cells. The siphunculi are attenuated distally, and are 1.1-1.3 times as long as the cauda (cf. Uroleucon erigeronense, which has siphunculi which are 1.8-2.3 times the length of the cauda). The body length of adult Uroleucon caligatum apterae is 3.2-4.0 mm.

Note: Uroleucon caligatum is closely related to Uroleucon luteolum, which has a more southerly distribution in USA, and apparently differs only in the lack of spinal tubercles. Blackman in Aphids on Worlds Plants comments that further studies are needed, as the development of these tubercles is likely to be environmentally determined.

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

Alatae (see second picture above) are very similar in colour to apterae, but with a slightly browner thorax and red pigment spots around the ocelli. Antennal segment III has 24-50 secondary rhinaria distributed over the whole length of the segment on one side. Immature Uroleucon caligatum (see pictures below) also resemble the adult apterae, but with mainly brown rather than black siphunculi, with pale bases.

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

Uroleucon caligatum feeds on goldenrod (Solidago species). Moran (1984) notes that Solidago canadensis, Solidago altissima, Solidago gigantea, Solidago rugosa are the hosts most colonized in nature, but Solidago altissima supports faster development than Solidago canadensis or Solidago gigantea (Moran, 1981). The species is common in north-eastern USA and Canada.

 

Other aphids on the same host

Uroleucon caligatum has been recorded from 7 goldenrod species (Solidago altissima, Solidago caesia, Solidago canadensis, Solidago gigantea, Solidago juncea, Solidago odora, Solidago rugosa).

Acknowledgements

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

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 Richards (1966) and Richards (1972) 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.A. (1981). Intraspecific variability in herbivore performance and host quality: a field study of Uroleucon caligatum (Homoptera: Aphididae) and its Solidago hosts (Asteraceae). Ecological Entomology 6, 301-306. 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

  • Richards, W.R. (1966). A new species of Dactynotus Rafinesque (Homoptera: Aphididae). The Canadian Entomologist 98(3), 312-314. Abstract

  • 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