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Dysaphis aucupariae

Wild service aphid

Identification & Distribution  Biology & Ecology 

Identification & Distribution:

Apterae of Dysaphis aucupariae on their primary host are greyish green or pinkish yellow with distinctive brownish to reddish areas at siphuncular bases (see first picture below). The head, antennae (except segment III), legs, siphunculi and cauda are all dark. Their antennae are about 0.6 to 0.7 times the body length. The dorsum of Dysaphis aucupariae is membranous with cross bars on the thorax and abdominal tergites VI and VIII only, and smaller sclerites on other segments. The siphunculi are 2.5 to 3.1 times the length of the triangular cauda. Their body length is 2.2-2.6 mm.

 

Guest images copyright Dr Jula Werres, INRES,  all rights reserved

Older specimens are heavily wax-powdered (see second picture above). Dysaphis aucupariae apterae on the secondary host are pinkish ochreous with reddish or brownish areas at the siphuncular bases. The alate viviparous female from the primary host has the abdomen ochreous to greenish-yellow with a black trapeziform dorsal patch on tergites III-V and spinal cross bands on tergites I and II. The Dysaphis aucupariae alate from the secondary host is reddish ochreous with a blackish sclerotic pattern.

Dysaphis aucupariae host alternates. The spring generations of Dysaphis aucupariae live in reddish to yellowish rolled or twisted pseudogalls on the leaves of Sorbus torminalis (wild service tree). The secondary hosts are various plantain species (Plantago lanceolata, Plantago media, Plantago major) where they live in the grooves between the veins on the undersides of the leaves. They are often attended by ants. Dysaphis aucupariae is found in Europe east to Crimea and the Caucasus and the Azores. It has (presumably) been introduced to Australia, New Zealand, Argentina and Washington, USA.

 

Biology & Ecology:

Until this year we had not found Dysaphis aucupariae in Britain, and we are very grateful to Dr Jula Werres (INRES, Bonn, Germany) for most of the images displayed. Jula reports that the damage pattern is similar each year. In late April the leaves get curled with the aphids inside (see picture below).

Guest image copyright Dr Jula Werres, INRES,  all rights reserved

The pseudogall of Dysaphis aucupariae is characteristic. It is initially pale yellow green but soon becomes tinged with red. In 2015 we found the characteristic red-tinged leaf galls of Dysaphis aucupariae in Britain - at the Bedgebury Pinetum in Kent as shown in the first picture below. Finally the galls turn golden yellow (see second picture below).

 

Second image above copyright Dr Jula Werres, INRES,  all rights reserved

Colonies in the pseudogalls are heavily waxed and often attended by ants. Despite this, predators are usually present, especially syrphid larvae (see second picture below).

 

Guest images copyright Dr Jula Werres, INRES,  all rights reserved

Parasitoids also enter the galls. The picture below shows a mummified aphid from a leaf gall in Kent.

Sometimes the entire tree is infested and then, some weeks later, the whole tree is bare branched. Sunde (1984)  records the apparent establishment of a Dysaphis aucupariae population in New Zealand. Since the wild service tree is not present in New Zealand, it is generally assumed that the population is maintaining itself on the secondary host. Buckton (1877) reports that the species also feeds on rowan (Sorbus aucupariae) which is found in New Zealand. Possibly it does use rowan in New Zealand, but in Europe it is found far more often on wild service tree .

Acknowledgements

Our sincere thanks to Jula Werres for the pictures shown above. We also thank the UK Forestry Commission Bedgebury Pinetum  for their kind assistance, and permission to sample.

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

  •  Sunde, R.G. (1984). New records of plant pests in New Zealand 4. 7 aphid species (Homoptera: Aphidoidea). New Zealand Journal of Agricultural Research 27, 575-579.