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Greenideinae : Schoutedenii : Schoutedenia ralumensis
 

 

Schoutedenia ralumensis

Two-tailed euphorb aphid

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

Identification & Distribution

Adult apterae (see first picture below) of Schoutedenia ralumensis are lemon-yellow or green. Antennal tubercles are absent. The antennae are 5-segmented, 0.4-0.75 times as long as the body, with a terminal process usually more than 0.5 times the base of antennal segment VI (cf. Schoutedenia emblica, where the terminal process is usually less than 0.5 times its base). The apterae lack secondary rhinaria. Antennal hairs are about 0.5 times the basal diameter of segment III. The head is fused with the prothorax, and eyes are represented only by triommatidia. The apical rostral segment (RIV+V) is about 0.05 times the second hind tarsal segment, and shorter than the antennal terminal process (cf. Schoutedenia emblica, which has RIV+V longer than the terminal process). Femora and trochanters are fused. First tarsal segments have 3 hairs. Thoracic spiracles have unusually large bases; spiracles of abdominal segments I-VI are rather more rounded than usual, but of normal size. Abdominal marginal sclerites are not pigmented. Abdominal segment VII bears a pair of long projections. The siphunculi are conical and bear 4 hairs. Tergite VIII is very small, and the cauda is broad and carries 4 long conspicuous hairs. Body length of adult Schoutedenia ralumensis apterae is 1.4-1.8 mm.

Note: Liu et al. (2013) suggest that, given the morphological characters and their molecular data, the validity of the only other recognised member of the genus, Schoutedenia emblica, is doubtful, and it may be a synonym of Schoutedenia ralumensis.

Images above copyright Nick Lambert,/a> under a Creative Commons Attribution 3.0 License.

In the alatae, secondary rhinaria are distributed 18-65 on antennal segment III, 1-9 on segment IV, and usually none on V. The head of the alate is distinct from the thorax and bears compound eyes. The forewing veins are thickly black-bordered. The forewing media vein is once branched, and the hindwings are without oblique veins.

Schoutedenia ralumensis is monoecious, with a much wider host range than Schoutedenia emblica, feeding on young shoots, leaves and stems of several genera in the Phyllanthaceae (= Euphorbiaceae), including Breynia, Bridelia, Flueggea, Glochidion, and Phyllanthus. They are partially holocyclic, with oviparae and alate males occurring with parthenogenetic generations through the summer and autumn. Fundatrices are present in spring. Schoutedenia ralumensis is widespread in south-east Asia, India, Africa and the east coast of Australia.

 

Other aphids on the same host

Schoutedenia ralumensis has been recorded on 6 Breynia species (Breynia cernua, Breynia disticha, Breynia fruticosa, Breynia oblongifolia, Breynia racemosa, Breynia vitis-idaea).

Schoutedenia ralumensis has been recorded on 3 Flueggea species ( Flueggea leucopyrus, Flueggea macrosipila, Flueggea virosa).

Acknowledgements

We are very grateful to Nick Lambert for putting his images of Schoutedenia ralumensis under a creative commons licence.

We have used the keys and species accounts of Eastop (1956) together with information from Liu et al. (2013), 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

  • Eastop. 1966. A taxonomic study of Australian Aphidoidea (Homoptera). Australian Journal of Zoology 14, 399-592. (p. 502) Abstract

  • Liu, Q-H. et al. (2013). DNA barcoding of Greenideinae (Hemiptera : Aphididae) with resolving taxonomy problems. Invertebrate Systematics 27, 428-438. Full text