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Dysaphis angelicae

Hawthorn - Angelica aphid

Identification & Distribution  Biology & Ecology 

Identification & Distribution:

On their primary host, hawthorn, Dysaphis angelicae fundatrices cannot be distinguished from others of the Dysaphis crataegi species group - please refer to Dysaphis crataegi (Hawthorn-carrot aphid)  for pictures of the fundatrix and gall. On their secondary host Dysaphis angelicae adult apterae (see first picture below) are greyish green with some white wax powdering. They also have a little reddish suffusion around the around the siphunculi, but this is much more prominent in immatures. Their antennae are short - about 0.3 times the body length. Their siphunculi are also quite short at 0.083-0.12 times the body length, but their length is more than twice their basal width.

The Dysaphis angelicae alate (see second picture above) has the bands on its doral abdomen fused to form a solid black patch.

The clarified mounts mounts below are of adult viviparous female Dysaphis angelicae (on secondary host) : wingless, and winged.

Micrographs of clarified mounts  by permission of Roger Blackman, copyright AWP  all rights reserved.

The hawthorn - angelica aphid host alternates between hawthorn (Crataegus spp.) as the primary host and angelica (Angelica sylvestris) as the secondary host. On the primary host Dysaphis angelicae induces a cherry-red leaf gall. All females of the second generation are winged and migrate. On the secondary host it forms colonies on the lower leaf bases. Dysaphis angelicae occurs throughout much of Europe.

 

Biology & Ecology:

Unlike most of the species using hawthorn as a primary host, Dysaphis angelicae is restricted to a single hostplant species, wild angelica (Angelica sylvestris) as its secondary host. Wild angelica has white or pinkish flowers in umbels, and can be distinguished from related species by its hairless, ridged purple stem and its inflated sheathing leaf petioles (see pictures below).

 

Dysaphis angelicae lives in quite large colonies on wild angelica between the sheathing leaf bases and the stem.

The colonies are usually attended by ants.

The picture above shows Myrmica ants in attendance of Dysaphis angelicae.

Colonies are also commonly attended by the common black garden ant (Lasius niger) (see first picture below). Depa & Wojciechowski, 2008  found Dysaphis angelicae living inside the nests of Lasius niger.

 

More rarely Formica ants are in attendance, as in the second picture above showing a southern wood ant (Formica rufa).

If ants are in attendance, there is seldom much evidence of predator activity.

 

However, in one unattended colony we found some aphids were parasitized by trombidiid mites (see first picture above), and a few predatory syrphid larvae were present (see second picture above).

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

  •  Depa & Wojciechowski (2008) Ant-root aphid relations in different plant associations. Polish Journal of Entomology 77, 151-163. Full text