Dysaphis angelicae

Identification & Distribution:

The fundatrix of Dysaphis angelicae induces a cherry-red to crimson curled-leaf gall on hawthorn (see first picture below). Neither the leaf gall nor the fundatrix of Dysaphis angelicae can be distinguished from others of the Dysaphis crataegi species group (the hawthorn-umbellifer aphids: Dysaphis angelicae, Dysaphis apiifolia, Dysaphis crataegi, and Dysaphis lauberti). The plump fundatrix of members of this group is bluish grey and densely powdered with wax. Their antennae are short at about 0.3 times the body length. The terminal process is 1.3-2.0 times the base of the last antennal segment. The siphunculi are quite short, about 0.08-0.09 times the body length and 1.4-1.8 times the cauda. The body length of the fundatrix is 1.7-2.3 mm. The generation produced in the gall are similarly heavily waxed (see second picture below) and nearly all develop to winged forms, known as 'spring migrants' or emigrant alates .

The alate can be identified to species. The Dysaphis angelicae emigrant alate has the bands on its doral abdomen fused to form a solid black patch (see third picture above). The longest hair on abdominal tergite III is more than 40 µm long (cf. Dysaphis apiifolia, and Dysaphis crataegi, where that hair is 40 µm or less). The total number of secondary rhinaria on antennal segment V (adding both sides together) is 0-31, but is never less than 6 in spring migrants, and usually exceeds 9 (cf. Dysaphis lauberti where the total number of secondary rhinaria on antennal segment V is usually 0-3, and never exceeds 9). On their secondary host (angelica), Dysaphis angelicae adult apterae (see fourth picture above) 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 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

On secondary host

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.

Ant attendance

Dysaphis angelicae 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).

Natural enemies

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).

Other aphids on same host:

Primary host

Dysaphis angelicae has been recorded from 4 Crataegus species (Crataegus calycina, Crataegus laevigata, Crataegus monogyna, Crataegus pentagyna).

Blackman & Eastop list 16 species of aphid as feeding on common hawthorn (Crataegus monogyna) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 15 as occurring in Britain (Show British list).

Secondary host

Dysaphis angelicae has been recorded from 2 Angelica species (Angelica archangelica, Angelica sylvestris).

Blackman & Eastop list 15 species of aphid as feeding on wild angelica (Angelica sylvestris) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 11 as occurring in Britain (Show British list).

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