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Cryptomyzus galeopsidis

European blackcurrant aphid

Identification & Distribution 

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 pictures below of Cryptomyzus galeopsidis on blackcurrant). Their siphunculi have the distal third slightly swollen, and are 1.1-2.1 times longer than the cauda. The body length of apterae is 1.3-2.6 mm.

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 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. The second picture below is a micrograph of Cryptomyzus galeopsidis in alcohol.

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.

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

The ovipara is yellowish without a green median stripe. The alate male has a dark dorsal patch and cross bands.

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 are currently regarded as 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.

Acknowledgements

Our particular thanks to Roger Blackman for images of his clarified slide mounts.

We also thank Plumpton College  and Trees for Life  for their kind assistance, and permission to sample.

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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