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Willow - umbellifer aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution:
Adult apterae of Cavariella pastinacae are rather light shiny green with appendages pale except for the base of antennal segment VI and the tarsi which are dark. Their antennae are about 0.45 times the length of the body and the terminal process is 3.0-4.0 times the base of the last antennal segment (cf. Cavariella aegopodi and Cavariella archangelicae where the terminal process is less than 2 times longer than the base of the last antennal segment ). The siphunculi are 2.3-3.0 times as long as the cauda and are slightly swollen towards the tip (cf. Cavariella theobaldi which does not have swollen siphunculi. Warning: this can be difficult to assess in live specimens). The supracaudal process is broadly tongue-shaped, with a flat apex and is 0.5-0.8 times the caudal length. The body length of Cavariella pastinacae apterae is 1.8-2.9 mm.
The Cavariella pastinacae alate has a dark abdominal patch formed by more or less fused cross bands on tergites III-VI. The antennae, cauda, supracaudal process and distal halves of siphunculi are dark.
The clarified slide mounts below are of adult viviparous female Cavariella pastinacae : wingless, and winged.
The willow - umbellifer aphid host alternates between willows (Salix species) and some umbellifers - mainly hogweed (Heracleum), wild parsnip (Pastinaca) and Angelica. Cavariella pastinacae is common over most of Europe and in North America.
Biology & Ecology
Cavariella pastinacae can develop very large colonies - the image below shows part of a colony on hogweed (Heracleum sphondylium).
Other aphids on same host:
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).