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Pleotrichophorus glandulosus

Bristly mugwort aphid

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

Identification & Distribution

Adult apterae of Pleotrichophorus glandulosus are yellowish white or greenish, sometimes with a pale green median stripe (see first picture below) (cf. Pleotrichophorus duponti which is dull greyish green with green transverse stripes). The antennal tubercles are fairly low with divergent inner faces. The antennae and legs are mainly pale with only the apex of the fifth antennal segment, the base of the sixth antennal segment, and the tarsi dark. The antennae have a very long terminal process. They have numerous thick, short capitate hairs hairs on the dorsum in 2-3 transverse rows on each segment. The siphunculi are long and slender, cylindrical over most of the length but slightly expanded at the tip with a small flange. The cauda is finger shaped. The body length of the adult Pleotrichophorus glandulosus aptera is 1.4-2.6 mm.

The alate Pleotrichophorus glandulosus (not pictured) has a yellowish abdomen with pale brown marginal sclerites and darker pleural intersegmental sclerites.

The bristly mugwort aphid lives on the undersides of the lower leaves of mugwort (Artemisia vulgaris). It can also be found on other Artemisia species and corn chamomile (Anthemis arvensis). Sexuales are produced in autumn with eggs laid on the leaf undersides. Pleotrichophorus glandulosus is found over most of Europe including Britain, and has been introduced to North America.

 

Biology & Ecology

We have only found Pleotrichophorus glandulosus on one occasion - on a large clump of mugwort growing in the car park of Malling Down Nature Reserve in East Sussex. They were not especially common, being present usually singly on only a small percentage of the lower leaves. The group of immatures pictured below was the largest group we found on one leaf.

The picture below shows an adult aptera Pleotrichophorus glandulosus with the first instar nymph she has just deposited.

They were sharing the habitat with large numbers of pointed snails (Cochlicella acuta, see picture below), a species which prefers calcareous soils as present at Malling Down on the South Downs of England.

Takada (1966)  described the new species of parasitoid Lysaphidus pleotrichophori. It parasitizes Pleotrichophorus glandulosus on Artemisia species. The mummies are pale yellowish brown.

 

Other aphids on same host:

Blackman & Eastop list 73 species of aphid  (including 28 Macrosiphoniella species) as feeding on mugwort (Artemisia vulgaris) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015)  lists 25 as occurring in Britain: Aphis aurantii,  Aphis fabae,  Aphis gossypii,  Aphis spiraecola, Aulacorthum solani,  Brachycaudus cardui,  Brachycaudus helichrysi,  Coloradoa artemisiae, Coloradoa heinzei, Coloradoa rufomaculata, Cryptosiphum artemisiae, Macrosiphoniella abrotani, Macrosiphoniella absinthii,  Macrosiphoniella artemisiae,  Macrosiphoniella oblonga,  Macrosiphoniella pulvera,  Macrosiphoniella sanborni, Macrosiphoniella tanacetaria,  Myzus ascalonicus,  Myzus ornatus,  Myzus persicae,  Pleotrichophorus glandulosus, Protrama flavescens, Smynthurodes betae  and Trama troglodytes. 

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

  • Takada, H. (1966). Three new aphid species of the genus Lysaphidus Smith from Japan (Hymenoptera: Aphidiidae). Insecta matsumurana 28 (2), 127-130. Full text