Cryptomyzus ballotae

Identification & Distribution:

Adult apterae of Cryptomyzus ballotae (see first picture below) are dark grey-blue to mottled light green. Their antennae are 1.1 to 1.3 times the body length, with a terminal process that is 5.9-9.0 times the length of the base of antennal segment VI. The apical segment of the rostrum is 1.5-1.6 times the length of the second hind tarsal segment. The body and appendages have numerous thick capitate hairs, visible in the micrograph of an aptera in alcohol below. Abdominal tergite III of Cryptomyzus ballotae has 2 pairs of equally long spinal hairs, 1-2 pairs of pleural hairs, and 3-5 pairs of marginal hairs. The siphunculi of Cryptomyzus ballotae are swollen on the distal part and are 3.7-4.1 times the length of the rounded triangular cauda. The body length of adult apterae is 1.7-2.1 mm.

The micrograph below shows the numerous thick capitate hairs on the body and appendages.

The alate female has a large quadrangular dorsal patch on tergites III-VI (see second micrograph below), as well as marginal and pleural sclerites. The clarified slide mounts below are of an adult viviparous female Cryptomyzus ballotae: wingless and winged.

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

The hairy horehound aphid does not host alternate. It feeds on black horehound (Ballota nigra) and other Lamiaceae including white dead-nettle (Lamium album), red dead-nettle (Lamium purpureum) and balm (Marrubium vulgare). Oviparae and alate males have been obtained in the laboratory, but the species is thought to mainly overwinter as parthenogenetic viviparae. Cryptomyzus ballotae is distributed over most of central, western and southern Europe.

Other aphids on same host:

Blackman & Eastop list 6 species of aphid as feeding on black horehound (Ballota nigra) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015) lists 5 as occurring in Britain: Aphis ballotae, Aulacorthum solani, Cryptomyzus alboapicalis, Cryptomyzus ballotae and Myzus ornatus.

Acknowledgements 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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