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Mallow aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution:Adult apterae of Brachycaudus malvae are pale green with separate black cross bars on thoracic segments, and an extensive shining black sclerotic shield on the dorsum. The hairs on the third antennal segment are very short, only 0.2-0.25 times the basal diameter of that segment. The last two fused apical rostrall segments (RIV + V) are 0.165-0.190 mm in length. The siphunculi are black and cylindrical. The body length of Brachycaudus malvae apterae is 1.8-2.3 mm.
The clarified slide mounts of adult viviparous female Brachycaudus malvae : wingless, and winged are shown below.
Brachycaudus malvae lives all year feeding on mallow (Malva) species with no host alternation. Aphid colonies are usually attended by ants. Sexual morphs have apparently not been described. The species is found in Britain, Spain, Italy, southern Russia, Ukraine and China (an odd distribution suggesting the species has been overlooked in many countries).
Biology & Ecology:
There is a real dearth of information about Brachycaudus malvae in the literature. Coeur d'acier (2007) using molecular techniques notes that Brachycaudus malvae is most closely related to Brachycaudus jacobi, a species which utilizes a quite different host family (Boraginaceae). Jousselin et al. (2010) uses Brachycaudus malvae as an example of how speciation in the genus has been via the acquisition of new somewhat distantly related hosts (in this case Malva) during the summer phase of the heteroecious (host alternating) life cycle.
In Britain Baker (2009) found large colonies of Brachycaudus malvae feeding on several common mallow (Malva sylvestris) plants, growing on the edge of a pebble beach at The Knap, Barry, in Wales during summer 2008. Feeding was concentrated on basal parts of the plants where they were sheltered by Lasius niger, but some aphids moved to feed on aerial parts as summer progressed.
We have found Brachycaudus malvae on several occasions in southern England, both in East Sussex and in Bedfordshire. The picture below shows a dense colony on mallow in East Sussex, with a single adult aptera and numerous immatures.
The pictures below show micrographs of a normal apterous adult of Brachycaudus malvae and of an apparently albino example of the same species.
Other aphids on same host:
Blackman & Eastop list 20 species of aphid as feeding on Mallow (Malva species) worldwide, and provide formal identification keys.
Of those aphid species, Baker (2015) lists 17 as occurring in Britain: Aphis craccivora, Aphis fabae, Aphis frangulae, Aphis gossypii, Aphis nasturtii, Aphis solanella, Aphis spiraecola, Aphis umbrella, Acyrthosiphon malvae, Aulacorthum solani, Brachycaudus helichrysi, Brachycaudus malvae, Macrosiphum euphorbiae, Myzus ascalonicus, Myzus ornatus, Myzus persicae and Rhopalosiphum rufiabdominale.