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Uroleucon cirsii

Large thistle aphid

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

Identification & Distribution:

Uroleucon cirsii apterae (see first picture below) are 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. Crescent shaped antesiphuncular sclerites are present (cf. Uroleucon aeneum and Uroleucon jaceicola which do not have antesiphuncular sclerites). 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 yellow cauda has 20-33 hairs (cf. Uroleucon aeneum which has a black cauda). Uroleucon cirsii is a rather large aphid with a body length of 3.2-5.2 mm.

The alate (see second picture above) is bronzy or reddish brown much like the aptera with a pale cauda and pale legs that are darkened towards the apices of the segments.

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. Oviparae and dark green males appear in late September to October, and eggs are laid on the undersides of the radical leaves. Uroleucon cirsii is found throughout Europe and has been introduced to North America.

 

Other aphids on same host:

Uroleucon cirsii has been recorded from 12 Cirsium species.

Acknowledgements

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

Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made 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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