Brachycolus cucubali

Identification & Distribution

Brachycolus cucubali produce a leafroll pseudogall (see first picture below) on their host, campions (Silene species), by rolling the leaves inwards and compacting the inflorescence. The aphids live and feed in the pseudogall. They also cause stem-shortening and malformations of the plant.

Images above by permission Sébastian Carbonnelle, all rights reserved.

Adult apterae of Brachycolus cucubali (see second picture above, and first below) are pale green to whitish yellow, with the head, legs, siphunculi and cauda dark, and dark cross-bars on tergites VII and VIII. The live aphids are covered with white wax-powder. The antennae are 0.40-0.52 times as long as the body, with the terminal process 1.29-2.30 times the base of antennal segment VI. The longest hair on antennal segment III is about 0.6 times the basal diameter of the segment. The rostrum reaches to the middle coxae, with the apical rostral segment 0.68-0.79 times the second hind tarsal segment, with 2-4 accessory hairs. The siphunculi are barrel-shaped, wrinkled, very short, only 0.39-0.53 times the caudal length, without a well developed flange. The cauda is oblong, triangular, obtuse, 1.1-1.6 times as long as broad, and with 6-8 hairs. The body length of adult Brachycolus cucubali apterae is 1.4-2.2 mm.

The alate viviparae of Brachycolus cucubali (see clarified mount in second picture above) are similar to the apterae, but have marginal and dorsal sclerites, and crossbars on the posterior abdominal tergites. The antennae are 0.68-1.01 times the body length, and the terminal process is 1.86-2.61 times the base of antennal segment VI. Secondary rhinaria are distributed 9-16 on antennal segment III and 0-2 on segment IV.

Brachycolus cucubali are monoecious on campion (Silene spp.), rolling the leaves into pseudogalls. There are also unconfirmed reports from Kazakhstan of them feeding on other Caryophyllaceae, namely Cerastium davuricum, Cerastium tianschanicum & Saponaria officinalis. It has long been assumed they are holocyclic, given their similarity to other Brachycolus species, but until recently the sexuales had not been observed. However, Casiraghi et al. (2020) have now described the ovipara and the small apterous male. Some apterous viviparae also live through the winter within the galls. Brachycolus cucubali is found over much of Europe, extending to eastern Siberia, Kazakhstan and north Africa.

Other aphids on the same host

Brachycolus cucubali has been recorded on 4 campion species (Silene behen, Silene chlorantha, Silene nutans, Silene vulgaris).

• Blackman & Eastop list 16 species of aphid as feeding on bladder campion (Silene vulgaris) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).

Acknowledgements We are grateful to Sébastian Carbonnelle for permitting us to reproduce his images of Brachycolus cucubali. Our particular thanks to Roger Blackman for images of his clarified slide mounts. We have used the species accounts given by Heie (1992) (as Hayhurstia cucubali) and Casiraghi et al. (2020) together 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 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 Casiraghi, M.-G. et al. (2020). Description of sexuales of Brachycolus cucubali (Passerini, 1863) (Hemiptera Aphididae). Redia 103, 47-53 (p. 47) Full text Heie. 1992. The Aphidoidea (Hemiptera) of Fennoscandia and Denmark. IV. Family Aphididae: Part I of tribe Macrosiphini and subfamily Aphidinae. Fauna Entomologica Scandinavica 25, 96.