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Waxy meadow-rue aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Aphis thalictri are bluish grey to greenish brown, with often heavy wax deposits in transverse bands across the dorsum. The frons has weakly developed antennal tubercles. The antennae are 6-segmented, about 0.6-0.7 times body length, and with the terminal process 1.5-1.7 times the base of antennal segment VI. The longest hair on antennal segment III is 0.7-1.2 times the basal diameter of that segment. There are no secondary rhinaria on the aptera. The rostrum does not reach behind the hind coxae. The dorsum is membranous, with a narrow dark cross bar on tergites VII and VIII, and intersegmental muscle sclerites. There are small conical marginal tubercles on the prothorax and abdominal segment VIII, and flat marginal tubercles on tergite I. The siphunculi are nearly cylindrical, wrinkled and very short, only about 0.02 times body length and 0.3-0.4 times the cauda. The cauda is rather broad, more or less triangular with an acute apex, hardly longer than its basal width, and with 9-12 hairs (cf. Longicaudus trirhodus, which has the cauda finger-like and much longer than its basal width). The body length of adult Aphis thalictri apterae is 2.0-2.8 mm.
First image above copyright Gennadiy Okatov; second image copyright Vyacheslav Yusuppov,
Alate viviparae of Aphis thalictri have 5-11 secondary rhinaria on antennal segment III, and 0-2 on IV. The abdomen has rather large marginal and small postsiphuncular sclerites, with several small sclerites or cross bars on most tergites. Marginal tubercles may be present on some tergites.
Image copyright Felix Riegel, under a cc by-nc-sa licence.
Aphis thalictri is monoecious on meadow-rue (Thalictrum spp.). In spring they feed on the leaf undersides and up the stems, moving to the inflorescences in summer and autumn. Stroyan (1984) states that they are mainly found on Thalictrum aquilegifolium, but apparently not on Thalictrum minus. Despite this, the observation from Russia (see first image on page) was on Thalictrum minus. They are thought to be holocyclic, but sexuales do not seem to have been described. Bozhko (1976) considered a population from Thalictrum sp. in Ukraine to be a subspecies, Aphis thalictri ssp. orangii. Aphis thalictri is found in northern and central Europe into Russia and Central Asia, and apparently North Korea. It has also been reported from Canada.
Other aphids on the same host
Aphis thalictri has been recorded from at least 13 Thalictrum species (Thalictrum aquilegiifolium, Thalictrum collinum, Thalictrum delavayi, Thalictrum fendleri, Thalictrum flavum, Thalictrum foetidum, Thalictrum lucidum, Thalictrum minus, Thalictrum minus kemense, Thalictrum minus pseudominus, Thalictrum petaloideum, Thalictrum simplex, Thalictrum speciosissum).