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Dysaphis ranunculi

Hawthorn-buttercup mealy gall aphid

Identification & Distribution  Biology & Ecology  Damage & Control 

Identification & Distribution:

The curled-leaf gall of Dysaphis ranunculi on the primary host, hawthorn, (see first picture below) is pale yellowish-green, often suffused with rosy pink (our gall was yellowish green but had no pink colour). There is no sharp demarcation between the pink of the gall and the green of the leaf lamina (cf. Dysaphis crataegi  where such a demarcation is present). The Dysaphis ranunculi fundatrices are deep blue-grey with a wax bloom, and the immature offspring of the fundatrix are usually brownish grey to grey. The immature offspring in the gall shown below second were light green with wax markings - hence the identification of this gall as resulting from Dysaphis ranunculi, based on gall-appearance, may not be correct.

 

Winged forms arise in the second generation and the alates migrate to the basal parts of buttercups (Ranunculus spp.). On Ranunculus the adult Dysaphis ranunculi apterae are mottled grey-green, brownish around the bases of the siphunculi, wax dusted and with variable dark sclerotization. There are usually 9 or more secondary rhinaria on the fifth antennal segment (cf. Dysaphis crataegi where there are usually 0-1).

The images below show confirmed Dysaphis ranunculi living on the roots of the secondary host, Ranunculus (no other Dysaphis species live on Ranunculus.) The first is an apterous immature and the second is a fourth instar alatiform nymph.

 

Colonies are attended by ants. There is a return migration to hawthorn in September. The hawthorn-buttercup aphid is found throughout Europe and in central Asia.

Acknowledgements

We especially thank Trees for Life  for their kind assistance.

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).

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