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Aphis fabae species-group
Black Bean aphidIdentification & Distribution Other aphids on the same host
Identification & Distribution:Aphis fabae is a black or very dark brown aphid species with a variable abdominal sclerotic pattern - confined to abdominal tergites 6-8 in smaller apterae, but broken bands are present in larger ones. Their siphunculi and cauda are dark. Aphis fabae antennae have joints of III-IV and base of V are usually quite pale. Marginal tubercles are protuberant but small. The longest femora and tibial hairs are longer than the least width of tibiae. The Black bean aphids' apterae (see second picture below) often, and immatures (see first picture below) very often, have discrete white wax spots. The body length of Aphis fabae apterae is 1.2-2.9 mm.
The clarified slide mounts below are of adult viviparous female Aphis fabae : wingless, and winged.
The black bean aphid host alternates between spindle (Euonymus europaeus) as the primary host and many herbaceous plant species as secondary hosts. Sexual forms occur in autumn. Aphis fabae is found throughout the northern continents, and has been introduced to many tropical and subtropical countries where it may reproduce parthenogenically all year round. In Europe there is a complex of sibling species or subspecies which can only be distinguished by their choice of secondary host coupled with transfer experiments.
Aphis fabae sibling species / subspecies
The nominate subspecies Aphis fabae fabae migrates to both broad beans (Vicia faba) (pictured above first) and poppies (Papaver spp.) (pictured above second) as well as Chenopodium species and beet (Beta vulgaris). Aphis fabae fabae will not colonise thistle (Cirsium) or black nightshade (Solanum).
Aphis fabae cirsiiacanthoidis migrates to thistle (Cirsium arvense) (pictured above first) and Aphis fabae mordvilkoi to burdock (Arctium) (pictured above second). The fourth subspecies is Aphis fabae solanella, which migrates to black nightshade (Solanum nigrum).
Although one can tentatively assign Aphis fabae on the plants above to a particular subspecies, they also colonise a huge range of other plants (for example many umbellifers) which are not associated with a particular subspecies. Also some hosts such as docks (Rumex spp) seem to be acceptable to all Aphis fabae subspecies. Lastly (just to confuse things further) what was called Aphis euonymi has now been renamed Aphis fabae evonymi, and Aphis fabae solanella has been renamed as Aphis solanella.
Other aphids on same host:Blackman & Eastop list 7 species of aphid as feeding on spindle (Euonymus europaeus) worldwide, and provide formal identification keys. Baker (2015) lists all 7 as occurring in Britain: Aphis aurantii, Aphis fabae cirsiiacanthoidis, Aphis fabae euonymi, Aphis fabae fabae, Aphis fabae solanella, Macrosiphum euphorbiae and Myzus persicae