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Schoutedenia aphidsOn this page: Schoutedenia emblica
Schoutedenia lack antennal tubercles and the median frontal tubercle. The antennae are 5-segmented, and are 0.51-0.78 times as long as the body. Apterae have no secondary rhinaria, but alatae have 8-47 rhinaria on antennal segment III, & 2-12 on segment IV. The eyes are triommatidia. The apical rostral segment is 0.73-1.00 times the second hind tarsal segment. The prothorax is fused with the head. First tarsal segments have 3 hairs. Abdominal tergites I-VIII are reticulated. Tergite VII has two pale brown processes pointing backwards, and tapering gradually from base to apex. The siphunculi are cones with concentric imbrications. The cauda is without a median process, and bears 4 hairs.
There are currently only two species of Schoutedenia recognised. Both are monoecious on woody Euphorbiaceae and Phyllanthaceae. More species were originally described, but these have since been synonomized, and it is still uncertain whether the two current species are distinct. Both species are holocyclic.
Schoutedenia emblica (Indian gooseberry aphid) East & South Asia
Adult apterae of Schoutedenia emblica (see first picture below) are olive green with (usually faint) orange-buff patches. Antennal and median frontal tubercles are almost absent. The antennae are 5-segmented, about 0.5 the body length, and with a terminal process usually less than 0.5 times the base of antennal segment V (cf. Schoutedenia ralumensis, whose terminal process is more than 0.5 times the length of its base). There are no secondary rhinaria on antennal segment III. The eyes are very small and composed of only 3 facets (triommatidia). The rostrum reaches to the third pair of coxae, with the apical rostral segment (RIV+V) longer than the antennal terminal process (cf. Schoutedenia ralumensis, which has RIV+V shorter than the terminal process). Abdominal tergite VI has a pair of large, backwardly-pointed processes. The siphunculi are cone-shaped, and very short, only about 0.05 times the body length. The cauda is broadly oval with two long hairs. The second picture below shows a clarified slide mount of an apterous adult.
Images above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka (accessed 12/2/20).
The alate Schoutedenia emblica (see third picture above) has 14-16 round secondary rhinaria evenly distributed on antennal segment III, and 1-2 on segment IV. The wings have a smoky appearance, with the veins dark bordered, and the borders widening at the apices of the veins. The hind wings are much reduced, without any oblique veins.
Schoutedenia emblica is monoecious on Indian gooseberry (Phyllanthus emblica =Emblica officinalis). Aphids cannot be easily detected on the host plants as their colonies at the bases of leaflets - and these are concolourous with their body colour. The species is holocyclic. Apterous or brachypterous males, and oviparae are produced in August. Colonies are sometimes ant-attended. In India the aphid is present almost throughout the year with heavy infestations during winter. Schoutedenia emblica is found in India, Pakistan, Nepal, Thailand and China.