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Acyrthosiphon boreale

Northern cinquefoil aphid

Identification & Distribution  Biology & Ecology 

Identification & Distribution:

Adult apterae of Acyrthosiphon boreale are green with the anterior part of the body yellowish. The dorsal cuticle is slightly sclerotized and wrinkled, but not pigmented. The siphunculi are cylindrical with a rather well developed flange. The siphunculi are 0.21-0.30 times the body length and 1.5-2.6 times longer than the cauda. The cauda is rather thick, not constricted and bearing 7-11 hairs.

 

Their antennal tubercles are well developed with diverging, rough inner sides. The antennae are 0.7-1.1 the body length and the terminal process is 4.6- 6.0 times longer than the base of the sixth antennal segment. The third antennal segment of the aptera has 2-14 (rarely less than 5) slightly raised secondary rhinaria mainly on the basal half.

The fundatrix is similar to the aptera, but the terminal process is only 2.7 times longer than the base of the sixth antennal segment. Males are apterous.

Acyrthosiphon boreale lives year round on cinquefoils (Potentilla) species . It has a boreo-alpine distribution including northern Europe, Greenland and Canada.

 

Biology & Ecology:

We have only found Acyrthosiphon boreale on one occasion, a colony of the aphids on marsh cinquefoil (Potentilla palustris) in Inverness-shire in Scotland.

 

The colony comprised several adult apterae feeding on the stems and leaves of the host plant.

They were depositing first instar nymphs on the leaves close to the leaf mid-vein (see picture below).

Heie (2015)  notes that Acyrthosiphon boreale may be present in huge numbers on Potentilla species.

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

  •  Heie, O.E (2015). Aphidomorpha. In:Bocher, J. et al. The Greenland Entomofauna. An identification manual of insects, spiders and their allies. Brill. Leiden, The Netherlands.