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"It has long been an axiom of mine that the little things are infinitely the most important" |
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Uroleucon jaceaeLarge knapweed aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & Distribution:Uroleucon jaceae is a large blackish brown or reddish brown aphid, with rows of black spots on the dorsal abdomen (the spots are not very clear in life) (see first picture below). Abdominal tergites 2-4 often have small marginal tubercles about the size of hair bases. The femora have the basal half pale and distal half dark, with a rather sharp transition between them. The tibiae are totally black (cf. Uroleucon aeneum which has the tibiae brownish in the middle; also cf. Uroleucon jaceicola which has the legs mainly yellow with 'knees', tibial apices and tarsi black). The siphunculi are reticulated over the distal 0.16-0.27 of their length and are 1.3-1.8 times the length of the cauda. The cauda is black (cf. Uroleucon jaceicola which has a yellow cauda) and bears 18-30 hairs. The body length of Uroleucon jaceae apterae is 3.0-4.5 mm long.
The alate Uroleucon jaceae (see second picture above) has rather small marginal sclerites and 45-80 secondary rhinaria on antennal segment III. The micrographs below show ventral views of an adult aptera and an immature aptera of Uroleucon jaceae in alcohol.
The clarified slide mounts below are of adult viviparous female Uroleucon jaceae : wingless, and winged.
Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.
The large knapweed aphid lives on various knapweeds (Centaurea species) and a few other species of Asteraceae. Oviparae and alate males can be found from late September. Uroleucon jaceae is found throughout Europe, the Middle East, Central Asia and Pakistan. Other aphids on same host:Uroleucon jaceae has been recorded from at least 39 Centaurea species.
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