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Braggia eriogoniReticulated buckwheat aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & DistributionAdult apterae of Braggia eriogoni (see first picture below) are black or brownish black with a strong dorsal pattern of reticulation, accentuated by a white wax secretion (cf. Braggia deserticola, which has most of the dorsum shining dark brown). The wax-bordered reticulations cover all of the dorsum except dorsolateral areas of the mesonotum, the median portions of abdominal tergites II and III, and all of tergite V. The antennae beyond the middle of segment III are dusky. Antennal segments III & IV have conspicuous secondary rhinaria (cf. Braggia longicauda and Braggia urovaneta, both of which usually have antennae without secondary rhinaria). The rostrum is slender, reaching between the second and third pairs of coxae. The apical rostral segment (RIV+V) is usually less than 0.19 mm long (cf. Braggia columbiana in Oregon & Washington, which has RIV+V 0.19-0.24 mm long). The first tarsal segments are all with 3 hairs, or with 3 hairs at least on fore tarsi (cf. Braggia agathona in Colorado & Utah, which has first tarsal segments all with 2 hairs). The siphunculi are dark and strongly tapering. The cauda is dark, short, and less that 0.75 times its basal width. The body length of adult Braggia eriogoni apterae is 1.1-2.1 mm. Immatures (see pictures below) are reddish and wax dusted. Note: Hille Ris Lambers (1966) distinguished several subspecies of Braggia eriogoni (subspp. agathona, atra, californica, and eriogoni) on the basis of differences in hair length, siphuncular shape and extent of dorsal pigmentation. Blackman felt that more work was needed to justify the validity of these subspecies.
Images above copyright Jesse Rorabaugh under a public domain (CCO) licence. The pictures below are clarified slide mounts of an aptera and alate Braggia eriogoni. Note that the apical rostral segment (RIV+V) of the aptera pictured is only 0.16 mm in length - consistent with the criterion detailed above (i.e. < 0.19 mm). The alate Braggia eriogoni has the head and thorax blackish brown, and the abdomen yellowish olive-green mottled with olive-yellow, with dark bands on abdominal tergites VI-VIII and dark marginal sclerite on all segments. There is some reticulation on the dorsum, but much less than on the aptera. There are marginal tubercles on the prothorax, and on abdominal tergites I and VII.
First image above copyright Jesse Rorabaugh under a public domain (CCO) licence. Most Braggia species have a fairly narrow host range, but Braggia eriogoni is the exception. Pike (2009) has reported it as feeding on up to 17 different Eriogonum species. Colonies of aphids are found on the leaves, stems and especially the flowerheads of buckwheat. Braggia eriogoni is assumed to be monoecious holocyclic, but sexuales have not been described. Palmer (1952) reported the species as fairly common in Colorado & Idaho, with both apterae and alatae present from May to September. Braggia eriogoni is found in most of western USA. Other aphids on the same hostBraggia eriogoni has been recorded on at least 9 wild buckwheat species (Eriogonum alatum, Eriogonum arborescens, Eriogonum arcuatum, Eriogonum effusum, Eriogonum fasciculatum, Eriogonum heracleoides, Eriogonum inflatum, Eriogonum pyrolifolium, Eriogonum umbellatum).
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