Cavariella aegopodii

Identification & Distribution:

Cavariella aegopodii apterae are small and greenish or reddish. The tips of their antennae and apices of the legs are brownish. The antennae are about 0.4 times the body length, with the terminal process about 0.85-1.3 times the basal part of segment VI (cf. Cavariella archangelicae, Cavariella konoi, Cavariella pastinacae and Cavariella theobaldi which all have the terminal process more than 1.3 times the length of the basal part of segment VI). Cavariella aegopodii siphunculi are swollen and about twice as long as the cauda. The supracaudal process is 0.75-1.05 times the cauda, broadest at the base and oblong triangular to conical. The body length of Cavariella aegopodii apterae is 1.5-2.8 mm.

The clarified slide mounts below are of adult viviparous female Cavariella aegopodii : wingless, and winged.

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

The willow-carrot aphid host alternates from willows (Salix spp) to umbellifers (Apiaceae). The preferred primary hosts are crack willow (Salix fragilis) and white willow Salix alba, although some Willow species seem only to be colonized in spring, by winged forms from populations which have overwintered parthenogenetically. Preferred secondary hosts are cultivated umbellifers such as carrots (Daucus carota) and fennel (Foeniculum vulgare) and several wild umbellifers. Cavariella aegopodii is widespread throughout temperate and warm temperate parts of the world.

Other aphids on same host:

Primary hosts

Cavariella aegopodii has been recorded from more than 40 willow species worldwide.

• Blackman & Eastop list over 120 species of aphids as feeding on willows worldwide, and provides formal identification keys for aphids on Salix (Show World list). Of those Baker (2015) lists 21 as occurring in Britain (Show British list).

• Blackman & Eastop list 26 species of aphids as feeding on crack willow (Salix fragilis) worldwide, and provide formal identification keys (Show World list). Of these Baker (2015) lists 20 as occurring in Britain (Show British list).

• Blackman & Eastop list 41 species of aphid as feeding on white willow (Salix alba) worldwide (Show World list). Of those aphid species, Baker (2015) lists 25 as occurring in Britain (Show British list).

Secondary hosts

• Blackman & Eastop list 22 species of aphid as feeding on wild carrot (Daucus carota) worldwide, and provide formal identification keys (Show World list).

  Of those aphid species, Baker (2015) lists 16 as occurring in Britain (Show British list).

• Blackman & Eastop list 21 species of aphid as feeding on fennel (Foeniculum vulgare) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 16 as occurring in Britain (Show British list).

Acknowledgements 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).

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