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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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Aphis pilosellaeGreen mouse-ear hawkweed aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & Distribution:Adult apterae of Aphis pilosellae are pale to dark green, most commonly mottled green. Immature aphids are paler (see pictures below). Large apterae have dusky bands across tergites 7-8 or 6-8; small apterae have only faint dusky bars on 7-8. The most distinctive character of Aphis pilosellae is the long apical rostral segment (see first photomicrograph below) which is longer than antennal segment IV or V. The marginal tubercles on abdominal segments 1 and 7 are rather large (see second photomicrograph below).The siphunculi are 0.80 to 1.25 times the length of the cauda, which is tapering with very strongly incurved hairs. The body length of the Aphis pilosellae aptera is 1.02-1.54 mm. The alate Aphis pilosellae has marginal and postsiphuncular sclerites, bands on tergites IV-VIII, and often bars on a variable number of tergites I-V. The micrographs below show ventro-lateral and ventral views of an adult aptera Aphis pilosellae in alcohol.
The green mouse-ear hawkweed aphid lives under the rosette leaves and on the stolons of mouse-ear hawkweed (Hieracium pilosella). It is sheltered by ants under tents of soil particles. Sexual forms exist, but have not been described. In Britain it seems to be restricted to the south-east, possibly because it needs high sunshine levels. Aphis pilosellae is found throughout Europe and into Russia. Other aphids on same host:Blackman & Eastop list 18 species of aphid as feeding on mouse-ear hawkweed (Hieracium pilosella = Pilosella officinarum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 15 as occurring in Britain (Show British list).
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