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Aphididae : Aphidinae : Macrosiphini : Roepkea
 

 

Genus Roepkea

Roepkea aphids

On this page: Roepkea marchali

Roepkea [Macrosiphini]

Roepkea aphids resemble aphids in the (mostly) Nearctic genus Nearctaphis, but lack the marginal, abdominal, and prothoracic tubercles usually present on aphids in that genus.

Apterae on the primary host (fundatrigeniae) have the antennal and median frontal tubercles poorly developed. Their antennae are 6-segmented, without secondary rhinaria. The rostrum reaches almost to the hind coxae. The prothorax and the abdomen are without marginal tubercles. The first tarsal segments each have 2 or 3 hairs. The cauda is short, and bluntly triangular.

Roepkea is a single species genus with Prunus as the primary host, rather than Pyroideae as in the case of Nearctaphis. Note that Richards (1969), included within Roepkea, 9 species now put in the genus Nearctaphis.

 

Roepkea marchali (Leaf-roll plum aphid)

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. On Prunus (their primary host) Roepkea marchali apterae vary in colour from almost black to dirty yellowish-green or orange-yellow (see second and third 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.

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

Apterae on secondary hosts are reputedly smaller, and have a body length of only 1.2-1.7 mm. They are usually dirty yellow-green, with variably-developed olive-green dorsal markings. 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.

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Acknowledgements

We are very grateful to Dr László Érsek for permission to reproduce his 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).

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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