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Uroleucon cirsii

Large thistle aphid

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

Identification & Distribution:

Uroleucon cirsii is a rather large aphid. It is bronzy or reddish brown with pale legs that are darkened towards the apices of the segments. Abdominal hairs are placed on pigmented scleroites. Spinal scleroites are fused into larger sclerites, each normally with three hairs. A crescent shaped sclerite is present in front of each siphunculus. The siphunculi are 0.25-0.34 times the body length, and 1.6-2.2 times the length of the cauda, with polygonal reticulation on less than the distal 0.25 of their length. The slightly dusky cauda has 20-33 hairs.

The clarified slide mounts below are of adult viviparous female Uroleucon cirsii : wingless, and winged.

Micrographs of clarified mounts  by permission of Roger Blackman, copyright AWP  all rights reserved.

The large thistle aphid is one of several species of aphids that lives on the leaves and stems of the creeping thistle (Cirsium arvense) and related species.


Other aphids on same host:

Blackman & Eastop list about 55 species of aphids  as feeding on Cirsium species worldwide, and provides formal identification keys for aphids on Cirsium. Uroleucon cirsii has been recorded from 12 Cirsium species.

Of the 36 species on creeping thistle (Cirsium arvense) Baker (2015)  lists 41 as occurring in Britain: Aphis fabae cirsiiacanthoidis,  Aphis gossypii,  Aphis nasturtii,  Aphis solanella,  Aulacorthum solani,  Brachycaudus cardui,  Brachycaudus helichrysi,  Capitophorus carduinus,  Capitophorus elaeagni,  Capitophorus gynoxanthus, Dysaphis lappae cirsii, Hyperomyzus lactucae,  Macrosiphum euphorbiae,  Myzus cymbalariae,  Myzus persicae,  Protaphis terricola,  Protrama radicis,  Smynthurodes betae,  Trama troglodytes,  Uroleucon aeneum,  Uroleucon cirsii, and Uroleucon jaceae. 


Our particular thanks to Roger Blackman for images of his clarified slide mounts.

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994)  and Blackman & Eastop (2006)  supplemented with Blackman (1974) , Stroyan (1977) , Stroyan (1984) , Blackman & Eastop (1984) , Heie (1980-1995) , Dixon & Thieme (2007)  and Blackman (2010) . We fully acknowledge these authors 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).

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