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Genus Pleotrichophorus

Bristly anthemid aphids

On this page: Genus Pleotrichophorus  Pleotrichophorus glandulosus 

Pleotrichophorus [Macrosiphini]

Pleotrichophorus are medium-sized pale spindle-shaped aphids. They have fairly low antennal tubercles and a moderately developed median frontal tubercle. The antennae have a very long terminal process, and both apterae and alatae have secondary rhinaria on some of the antennal segments. The terminal (fused 4th and 5th) rostral segment is pointed or stiletto-shaped. The apterae have a membranous dorsum, with numerous thick, rather short fan-shaped or capitate hairs in 2-3 irregular transverse rows on each segment. The siphunculi are long and slender, sometimes slightly expanded at the apex with a small flange, and the cauda is finger-shaped, tongue shaped or triangular.

Alates have dark intersegmental sclerites and dusky marginal sclerites. The veins on the forewings are conspicuously dark-bordered.

There are about 60 species of Pleotrichophorus worldwide, mostly in the Americas but with seven in Europe. They do not host alternate but remain all year on members of the Asteraceae, especially those in the tribe Anthemideae. Pleotrichophorus aphids are not attended by ants.

 

Pleotrichophorus glandulosus (Bristly mugwort aphid)

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.

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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 sp 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).