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Orange-bordered alder aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution
Adult apterae of Hannabura alnosa (see two pictures below) are pale green to creamy-white with a reddish-brown/orange line along each side of the body. The antennae are almost twice as long as the body length with the terminal process more than 4.5 times as long as the base of antennal segment VI. The antennal segments are mostly dark, apart from segments I & II and the basal parts of segments III and IV. The dorsum bears 4-6 capitate hairs per segment. The legs are mostly pale, but the apical thirds of the tibiae and tarsi are dark. The siphunculi are pale, short and truncate with a marked flange (cf. Illinoia alni and Illinoia wilhelminae, which have long, tubular siphunculi which are to some extent swollen on the apical third). The body length of adult Hannabura alnosa apterae is 1.3-1.6 mm.
Both images above by permission, copyright Claude Pilon, all rights reserved.
Immature Hannabura alnosa (see smaller individuals in first picture below) are very pale and lack the orange side markings. Alatae (see second picture below) are very pale green with antennae pigmented in a similar way to the apterae. The legs of alatae differ from those of the apterae in that the tibiae are completely dark.
Hannabura alnosa is only found on spectacled alder (Alnus rugosa =Alnus incana rugosa) where it feeds on the underside of the leaves along the midvein and other larger veins of the leaf. Pepper (1950) reports they adhere very closely to the veins and are difficult to see. They sometimes occur on the same leaves with Pterocallis alnifoliae. Sexuales occur in October and males are alate. The oviparae deposit their eggs on the bark around the same buds or other rough places as Pterocallis alnifoliae. Hannabura alnosa is only found in north-eastern North America.
Other aphids on the same host
Hannabura alnosa feeds on one species of alder (Alnus), namely Alnus rugosa (=Alnus incana rugosa).
Blackman & Eastop list 10 species of aphid as feeding on spectacled alder (Alnus rugosa) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).