Megoura viciae

Identification & Distribution:

Megoura viciae are large apple green to dark bluish green aphids. The adult aptera (see first picture below) has a black head and antennae, the latter being longer than the body. The prothorax is black, much narrower than the body which is green and globular. Black crescent-shaped sclerites are present in front of the siphunculi which are black and swollen in the middle, and about the same length as the cauda. The legs and cauda are also black.

The alate (see second picture above) has a green abdomen with black antesiphuncular and marginal sclerites, and dorsal cross bands on abdominal tergites 7 and 8.

The Megoura viciae clarified slide mounts below are of adult viviparous female Megoura viciae : wingless, and winged.

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

The vetch aphid does not host alternate but spends it entire life cycle on leguminous plants, especially vetch, Lathyrus and broad beans. Eggs are laid at the base of vetch or pea plants and hatch in spring. Populations build up and after three generations winged forms are produced which disperse to other plants. Megoura viciae generally move to the seed pods in autumn.

Other aphids on same host:

Megoura viciae has been recorded from 11 Vicia species.

Blackman & Eastop list 30 species of aphid as feeding on vetch (Vicia species) worldwide, and provide formal identification keys. Baker (2015) lists 21 as occurring in Britain: Acyrthosiphon loti, Acyrthosiphon pisum, Aphis aurantii, Aphis craccae, Aphis craccivora, Aphis fabae, Aphis gossypii, Aphis nasturtii, Aphis solanella, Aphis spiraecola, Aulacorthum solani, Brachycaudus helichrysi, Macrosiphum euphorbiae, Megourella tribulis, Megoura viciae, Myzus antirrhinii, Myzus cymbalariae, Myzus ornatus, Myzus persicae, Neomyzus circumflexus and Smynthurodes betae.

• Blackman & Eastop list 20 species of aphid as feeding on broad bean (Vicia faba) worldwide, and provide formal identification keys. Baker (2015) lists 17 of these as occurring in Britain: Acyrthosiphon pisum, Aphis evonymi, Aphis craccae, Aphis craccivora, Aphis fabae fabae, Aphis gossypii, Aphis solanella, Aphis spiraecola, Aulacorthum solani, Brachycaudus helichrysi, Macrosiphum euphorbiae, Megoura viciae, Myzus antirrhinii, Myzus ornatus, Myzus persicae, Smynthurodes betae and Toxoptera aurantii.

Megoura viciae has been recorded from 16 Lathyrus species.

Blackman & Eastop list 25 species of aphid as feeding on peavines or vetchlings, including 'sweet pea' (Lathyrus species) worldwide, and provide formal identification keys. Baker (2015) lists 16 as occurring in Britain: Acyrthosiphon loti, Acyrthosiphon pisum, Aphis craccae, Aphis craccivora, Aphis fabae, Aphis gossypii, Aphis pseudocomosa, Aphis solanella, Aulacorthum solani, Macrosiphum euphorbiae, Megoura viciae, Megourella purpurea, Myzus ornatus, Myzus persicae, Pemphigus populi and Smynthurodes betae.

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