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Wild crucifer aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution
Adult apterae of Lipaphis erysimi are small to medium sized yellowish green, grey green or olive green aphids, with a faint white wax bloom. The aptera (see first picture below) has two rows of dark bands on the thorax and abdomen which unite into a single band near the tip of the abdomen. The antennal terminal process is 0.8-1.15 times times the length of the siphunculi (cf. Lipaphis alliariae which has the antennal terminal process 1.2-1.35 the length of the siphunculi). The combined length of antennal segment III and the terminal process is usually less than 2.4 times the length of the siphunculus (cf. Lipaphis pseudobrassicae in which that combined length is usually more than 2.4 times as long as the siphunculus). The siphunculi are paler than the cauda and have dark tips. The body length of adult Lipaphis erysimi apterae is 1.4-2.4 mm.
Second image: Lipaphis erysimi alate, copyright Alan Outen & Rothamsted Research, all rights reserved.
Alatae (see second picture above) have a black head and thorax and a dusky green abdomen with black bands near the tip and conspicuous dark marginal sclerites. The body length of Lipaphis erysimi alatae is 1.4-2.2 mm. The clarified slide mounts below are of adult viviparous female Lipaphis erysimi : wingless, and winged.
The wild crucifer aphid does not host alternate. It feeds on various different Brassicaceae, including Brassica, Raphanus, and Sinapis spp., although it is not usually found on field Brassica crops. It lives on the undersides of leaves as well as on inflorescences, young shoots and growing points. Males have been found in some countries. Lipaphis erysimi is confined to Britain and northern continental Europe.
Biology & Ecology
Lipaphis erysimi is usually regarded as a relatively common aphid in Britain, but until recently we have found it to be rather scarce in southern England. Then in mid-October 2018 we found colonies of wild crucifer aphid on seed heads of hedge mustard (Sisymbrium officinale, see picture below).
Despite the lateness of the year, there was no sign of any sexual forms and the aphids were reproducing viviparously (see picture below).
Several of the colonies were comprised mainly of immatures (see picture below).
Then in late October we found much bigger colonies of Lipaphis erysimi on seedheads of shepherd's purse (Capsella bursa-pastoris). These however were mixed species colonies comprised of Lipaphis erysimi, Aphis fabae and Myzus persicae (see picture below).
Other aphids on same host: