Roepkea marchali

Identification & Distribution

In spring, feeding by the Roepkea marchali fundatrix on the undersides of leaves of Prunus mahaleb induces pseudogalls (see first picture below). The leaves become rolled into broad tubes, inflated and yellowed, and the aphids feed and develop inside the tubes.

Images above by permission, copyright Dr László Érsek, all rights reserved.

On Prunus (their primary host) Roepkea marchali apterae vary in colour from almost black to dirty yellowish-green or orange-yellow (see three pictures below), according to the degree of dorsal sclerotization, with rather short black siphunculi. The head capsule has spiculose ornamentation, and the antennal tubercles are poorly developed. The 6-segmented antennae are without secondary rhinaria. The antennal terminal process is 5.5-6.5 times the base of antennal segment VI, and the longest hairs on segment III are slightly longer than the basal diameter of that segment. The rostrum extends to slightly beyond the middle coxae. The body is densely spiculose and nodulose. There are no prothoracic or abdominal marginal tubercles. The siphunculi are short, nearly twice as long as the apical segment of the hind tarsus, with an apical flange and close-spaced transverse rows of small spicules. The cauda is short, broadly triangular, and without preapical constriction. The body length of adult Roepkea marchali apterae on the primary host is 1.5-2.3 mm.

Note: There is an eastern form, named Roepkea marchali ssp. bathiaschvili by Hille Ris Lambers (1966), recorded from Crimea, Georgia, Israel, Iran, Lebanon and Turkey. These aphids have a shorter antennal terminal process, and the apterae on Prunus tend to have dark dorsal cross-bands instead of a completely sclerotic tergum. Blackman notes that this subspecies name is not now accepted, as it was not accompanied by an adequate description (thus a 'nomen nudum').

Alatae of Roepkea marchali (not pictured) have a black dorsal abdominal patch and marginal sclerites. The antennae have numerous secondary rhinaria distributed 56-76 on segment III, 17-30 on segment IV, and (0-)2-6 on segment V. The rostrum extends to the middle coxae. Other characteristics are similar to the aptera.

The primary host of Roepkea marchali is mahaleb cherry (Prunus mahaleb). The life cycle is rather variable. In some countries (e.g. France) populations are monoecious holocyclic, remaining on mahaleb cherry all year without host alternation. In Italy there is a partial migration, to Galeopsis angustifolia (Lamiaceae), where in autumn they produce alate gynoparae and males that migrate back to Prunus. In eastern Europe and south-west Asia, there is regular host alternation to the flowers of Lamiaceae (Stachys, Phlomis). The aphids are ant-attended on the primary host. Roepkea marchali is found over Central & Southern Europe (not UK), into the Middle East and West Asia.

Other aphids on the same host

Primary host

Roepkea marchali has been recorded from 1 Prunus species (Prunus mahaleb).

• Blackman & Eastop list 12 species of aphid as feeding on mahleb cherry (Prunus mahaleb) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 9 as occurring in Britain (Show British list).

Secondary hosts

Roepkea marchali has been recorded from 2 Galeopsis species (Galeopsis angustifolia, Galeopsis tetrahit)

• Blackman & Eastop list 14 species of aphid as feeding on hemp nettles (Galeopsis species) worldwide, and provide formal identification keys. (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).

Roepkea marchali has been recorded from 2 Stachys species (Stachys annua, Stachys cretica)

• Blackman & Eastop list 6 species of aphid as feeding on annual yellow woundwort (Stachys annua) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 4 as occurring in Britain (Show British list).

Roepkea marchali has been recorded from one, undetermined, Phlomis species.

• Blackman & Eastop list 13 species of aphid as feeding on jerusalem sage (Phlomis) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 7 as occurring in Britain (Show British list).

Acknowledgements We are very grateful to Dr László Érsek and Marko Šćiban for permission to reproduce their images of the live aphids. We have used the genus and species accounts of Richards (1969), along with information from Hille Ris Lambers (1966), and 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 Hille Ris Lambers, D. (1966). Some synonyms in Aphididae. Ent. Ber. 26, 124-126. Full text Richards, W.R. (1969). A review of the holarctic genus Roepkea with descriptions of four new nearctic species. The Canadian Entomologist 101(11), 1121-1162. Abstract