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European blackcurrant aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution:
Adult apterae of Cryptomyzus galeopsidis on their primary host are pale greenish-white, or sometimes yellowish, often with a darker green spinal stripe (see first picture below). Their antennae are longer than the body with the antennal terminal process 9-14 times longer than the base of antennal segment 6. The longest hair on the third antennal segment is distinctly longer than the basal diameter of that segment. Abdominal segments I-V each have 6 thick capitate hairs, two spinal, two pleural and two marginal, arising from tuberculate bases (see first picture below of aptera on its secondary host - hemp nettle). Their siphunculi have the distal third slightly swollen, and are 1.1-2.1 times longer than the cauda. The body length of Cryptomyzus galeopsidis apterae is 1.3-2.6 mm.
Cryptomyzus galeopsidis alatae have a large quadrangular dorsal abdominal patch on tergites III-VI, which is more-or-less divided intersegmentally into broad cross bands. Antennal segment III has 40-60 prominent secondary rhinaria. The ovipara is yellowish without a green median stripe. The alate male has a dark dorsal patch and cross bands. The micrographs below show a Cryptomyzus galeopsidis from the primary host, dorsal and ventral in alcohol.
The micrographs below show clarified mounts of Cryptomyzus galeopsidis aptera and alate.
In spring Cryptomyzus galeopsidis lives on the underside of young leaves of blackcurrant (Ribes nigrum) and rarely on other Ribes species. It does not induce a gall on blackcurrant. In June it migrates to hemp nettle (Galeopsis), and other Lamiaceae, where it curls and rolls the young leaves. Some populations do not migrate from Ribes, and may be two subspecies of Cryptomyzus galeopsidis. The species is common and widespread throughout Britain and Europe, and is also found in the Russian Far East and North America.
Other aphids on same host:
Cryptomyzus galeopsidis has been recorded from 9 Ribes species.
Blackman & Eastop list 22 species of aphid as feeding on blackcurrant (Ribes nigrum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 14 as occurring in Britain (Show British list).
Cryptomyzus galeopsidis has been recorded from 7 Galeopsis species (Galeopsis angustifolia, Galeopsis bifida, Galeopsis ladanum, Galeopsis pubescens, Galeopsis segetum, Galeopsis speciosa, Galeopsis tetrahit), and 5 species of the Lamium genus (Lamium album, Lamium amplexicaule, Lamium galeobdolon, Lamium maculatum, Lamium purpureum).
Blackman & Eastop list 14 species of aphid as feeding on hemp nettles (Galeopsis species) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).