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Aphidinae : Aphidini: Braggia eriogoni
 

 

Braggia eriogoni

Reticulated buckwheat aphid

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

Adult 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.
Second image CBG group under a Creative Commons License.

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 host

Braggia 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).

Acknowledgements

We are grateful to Jesse Rorabaugh and Bold Systems CBG for making their pictures available for use under public domain and creative commons licences respectively.

We have used the keys and species accounts of Cowen (1895), Palmer (1952) (both as Aphis eriogoni), and Pike (2009), along with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections 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).

Useful weblinks

References

  • Cowen, J.H. (1895). In Gillette & C.F. Baker. A preliminary list of the Hemiptera of Colorado. Bulletin of the Colorado State University Agricultural Experiment Station 31, 21-137 (p. 119) Full text

  • Hille Ris Lambers, D. (1966). Notes on California aphids, with descriptions of new genera and new species. Hilgardia 97(15), 569-623. Abstract

  • Palmer, M.A. (1952). Aphids of the Rocky Mountain Region: including primarily Colorado and Utah, but also bordering area composed of southern Wyoming, southeastern Idaho and northern New Mexico. Thomas Say Foundation, Denver. Full text

  • Pike, K.S. et al. (2009). New species of Braggia (Hemiptera: Aphididae) on buckwheat in western North America. The Canadian Entomologist 141(6), 561-581. Full text