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Aphids on nettle (Urtica)

Species Overview: Aphis urticata  Microlophium carnosum 

Aphids on nettle

Blackman & Eastop list about 18 species of aphids  as feeding on Common stinging nettle (Urtica dioica) and 11 on Small nettle (Urtica urens) worldwide, and provides formal identification keys for aphids on Urtica.

Most of these, such as Neomyzus circumflexus (crescent-marked lily aphid) and Myzus ornatus (ornate aphid), are polyphagous and feed on a wide range of herbaceous plants. They are not commonly found on nettles, and we have yet to find them on this host. Hence we restrict this page to the two nettle specialists, both of which are common or abundant in Europe and North America. Assistance on differentiating the two species of nettle that we consider is given below. 

 

Aphis urticata (Dark green nettle aphid)

Aphis urticata is a small to medium size aphid. Early generations of the dark green nettle aphid are dark bluish-green with no wax covering and a body length of 1.7-2.2 mm. Later generations of apterae are yellow and much smaller with a body length of 0.9-1.4 mm. The antennae are shorter than the body length. The abdominal dorsum is either unsclerotized or rarely with rather narrow dusky bands across tergites 7-8. The pale siphunculi taper towards their tips which are usually slightly dusky. The tongue shaped cauda is also pale. Alates have more sclerotization than apterae with bands across tergites 7-8 and some marginal sclerites. The siphunculi of alates are uniformly dusky and cylindrical. The body length of the alate is 1.5-1.8 mm.

 

The dark green nettle aphid has a sexual stage in the life cycle but does not host alternate. It feeds on stinging nettle (Urtica dioica) and related Urtica species. In early summer it lives in dense colonies and causes leaf curl. Colonies are usually ant attended The summer dwarf apterae live scattered under the leaves. It is widely distributed and often common throughout Britain and the rest of Europe, the Middle East, parts of Asia and the USA.

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Microlophium carnosum (Common nettle aphid)

Microlophium carnosum is a large spindle-shaped aphid. The wingless adults are various shades of green, pink or reddish purple. The antennae are much longer than the full body length. The siphunculi are long - 2.3 to 3.1 times the length of the cauda - and tapering with flared apices. The siphunculi are markedly longer and more slender than those of Aphis urticata. The body length of apterae is 3.1-4.3 mm. The winged adult has dark marginal sclerites, but only faint spino-pleural markings.

 

There is a sexual stage in the life cycle, but there is no host alternation. Common nettle aphids live on stems and leaves of stinging nettle (Urtica dioica). They are generally common and often abundant throughout Europe and Asia east to Mongolia, Africa & North America. Unlike Aphis urticata, they are not ant-attended.

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Species of nettle

Two species of nettles occur commonly in Britain, the common or stinging nettle (Urtica dioica) and the small nettle (Urtica urens). The common nettle is a herbaceous perennial with creeping rooting stems which produce upright leafy stems up to about 150 cm tall with leaves about 6 cm. Male plants have flower clusters that stick out, whilst female plants have flower clusters that hang down.

The whole plant has large numbers of stinging hairs. These are the longer white hollow hairs visible in the picture below - the irritant poison is produced in the bulb at the base of each hair. If you brush against the plant, the tips of the hairs break off leaving a sharp point which can then penetrate the skin and inject the poison.

The small nettle is less common and is smaller, usually less than 30 cm tall with leaves only about 4 cm in length. It has more deeply excised leaves and both male and female flowers in the same cluster

Acknowledgements

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).

Useful weblinks 

References

  •  Blackman, R.L. & Eastop, V.F. Aphids on the world's plants An online identification and information guide. Full text