Dysaphis bonomii

Identification & Distribution:

Colonies of Dysaphis bonomii are attended by ants which tent the colony on the basal parts of Pastinaca sativa (wild parsnip), sometimes completely covering it with soil particles (see first picture below). The apterae which live under the tenting are pale to dull greyish green and are wax-dusted (see second picture below). The dorsal abdomen has complete dark cross bands on many or all of abdominal tergites 1-8. The siphunculi of Dysaphis bonomii are quite long and slender, 4 times or more longer than their basal diameters (see first micrograph below). The cauda is helmet shaped, a little shorter than its basal width in dorsal view (see second micrograph below). The body length of Dysaphis bonomii aptera is 1.2-2.5 mm.

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

The parsnip mealy aphid feeds on the basal parts of wild parsnip (Pastinaca sativa), and is attended by ants. It does not host alternate. Apterous males and oviparae occur in the autumn. Dysaphis bonomii has been found in a few European countries, namely (southern England, Sweden, Germany, Austria and Italy). They are monoecious holocyclic with apterous males.

Biology & Ecology:

Wild parsnip (Pastinaca sativa) (see below) is host to over 20 aphid species. The Parsnip mealy aphid (Dysaphis bonomii) is one of the less common species of aphid found on this plant. We found it at the edge of a salt marsh at Rye Harbour in East Sussex (see our December blog).

Dysaphis bonomii is distinguished by the complete, dark, cross-bands on many or all of its abdominal tergites and the slender siphunculi. The only references in research papers are a few observations of its occurrence on its host plant, parsnip (Pastinaca sativa).

The colonies may be very large and are commonly at the junction between a lower leaf and the stem. They may be located below the soil surface.

Dysaphis bonomii is often attended by ants. The colony below was attended by Lasius niger.

Other aphids on same host:

Blackman & Eastop list 23 species of aphid as feeding on wild parsnip (Pastinaca sativa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 18 as occurring in Britain (Show British list).

Acknowledgements We especially thank Rye Harbour Nature Reserve for their kind assistance, and permission to sample. Our particular thanks to Roger Blackman for images of his clarified slide mounts. Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made 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