Aphis craccae

Identification & Distribution

Adult apterae of Aphis craccae (see first picture below) are covered in a dense layer of grey wax powder (cf. Aphis craccivora, where the adult apterae have little or no wax on the dorsal surface, although immatures are waxed). Under the wax they have an extensive solid black shield on the dorsal abdomen which covers the whole width of tergites V and VI, and normally extends forward over the central areas of tergites I-IV, often with lateral extensions towards the intersegmental muscle sclerites. Their antennae are about the same length as the body, and the terminal process is 1.70-2.4 times the length of the base of antennal segment VI (cf. Aphis adesmiae, in South America, whose terminal process is 1.40-1.69 times the length of that segment). The dark siphunculi are 0.7-1.0 times as long as the dark, elongate, cauda (cf. Aphis craccivora, which has the siphunculi 1.1- 2.2 times the length of the cauda, and Aphis pseudocomosa, whose siphunculi are 1.1-1.6 times the caudal length). Abdominal tergite VIII usually has more than 2 hairs. The body length of adult Aphis craccae apterae is 1.9-2.8 mm.

The alatae (see second picture above) are also densely covered in grey wax powder, and have 5-13 secondary rhinaria on antennal segment III.

Aphis craccae lives in dense, ant-attended colonies (see third picture above) on the terminal growth, flowers and seed-pods of vetches (Vicia spp.), especially tufted vetch (Vicia cracca). Oviparae and alate males appear in September. The species is widely distributed in Europe, eastward to China, Japan and Korea. It has also been introduced into north-eastern USA and Canada.

Other aphids on the same host

Aphis craccae has been recorded on 13 species of vetch (Vicia) and on one species of Lathyrus (Lathyrus japonicus, but is most commonly encountered on tufted vetch (Vicia cracca).

Blackman & Eastop list 9 species of aphid as feeding on tufted vetch (Vicia cracca) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 7 as occurring in Britain (Show British list).

Blackman & Eastop list 20 species of aphid as feeding on broad bean (Vicia faba) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 17 of these as occurring in Britain (Show British list).

Acknowledgements We are especially grateful to Claude Pilon for pictures of Aphis craccae. 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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