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Genus Aspidaphis

Aspidaphis aphids

On this page: Genus Aspidaphis  Aspidaphis adjuvans 

Aspidaphis [Macrosiphini]

Aspidaphis are small dull green or yellowish brown aphids. They are characterised by having a cowl-like backward projection of abdominal tergites 8 which obscures the cauda in dorsal view. The antennae are short and have only 5 segments. Those of the apterae lack secondary rhinaria, whilst those of alates have secondary rhinaria on segments 3 or 3-4. The dorsum of the aptera is sclerotic or granulate with very short hairs. The siphunculi are either short, with the aperture positioned laterally before the tip, or are reduced to slightly elevated pores.

There are only two species in the genus Aspidaphis. They do not host alternate, and feed on either Polygonum (Aspidaphis adjuvans) or Festuca (Aspidaphis porosiphon).

 

Aspidaphis adjuvans (Wrinkly knotgrass aphid)

Adult viviparous apterae of Aspidaphis adjuvans are elongate oval in shape, and are coloured yellowish, brownish-yellow or pale bluish green. Their antennae are short and five segmented. The apical segment of the rostrum is obtuse and short, about 0.5 times the length of the second hind tarsal segment. The dorsum is strongly granulate, wrinkly, or warty in appearance with very few short hairs. The siphunculi are short thin tubes, only 0.03-0.04 times the body length; they are swollen distally and have a subapical aperture on the inner side (cf. Aspidaphis porosiphon on Festuca rubra which has the siphunculi as small pores with partly sclerotized rims hardly raised above the body surface). The triangular cauda is covered by a cowl-like backward projection of abdominal tergite 8. The body length of adult Aspidaphis adjuvans apterae is 1.3-2.0 mm.

Our pictures below show the ovipara rather than the adult vivipara. Oviparae are yellowish brown on the anterior and posterior dorsum, and bluish-green on the mid-dorsum.

The ovipara has swollen hind tibiae the underside of which bear 20-40 rather large and well-formed circular or oval scent glands.

Aspidaphis adjuvans lives all year round on its host, common knotgrass (Polygonum aviculare) or redshank (Persicaria maculosa). Apterous oviparae and narrow-bodied dark males are produced in autumn, with eggs laid on the senescing stems and leaves. The wrinkly knotgrass aphid has been recorded from England as well as most of continental Europe, Asia and 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).

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References

  •  Blackman, R.L. & Eastop, V.F. (2006). Aphids on the world's herbaceous plants and shrubs. Vols 1 and 2. John Wiley & Sons.