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Tormentil aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
Identification & Distribution:
Adult apterae of Aphis tormentillae (uppermost aphid in picture below) are rather small and very dark blackish green, appearing black in life. The antennae of the adult aptera often only have five segments. The dorsal abdominal pattern of Aphis tormentillae aptera is confined to bands across tergites 7-8, small dark intersegmental muscle sclerites and sometimes rudimentary marginal and postsiphuncular sclerites.There are small protuberant marginal tubercles on abdominal tergites 1 and 7. Their siphunculi are short and stout, 0.64-1.00 times the length of the cauda. The cauda is finger-shaped and dark like the siphunculi. The body length of the Aphis tormentillae adult aptera is 1.00-1.67 mm. Immatures are covered with a grey wax powder.
The alatae have larger marginal and postsiphuncular sclerites with a median sclerite on tergite 6.
Aphis tormentillae lives scattered in small numbers on the leaf bases and in the flowers of tormentil (Potentilla erecta). It does not host alternate. Sexual forms occur in autumn. The males are winged and the oviparae have rather strongly swollen hind tibiae. It is widely distributed in Britain but from very few counties mostly in Scotland. It has only been recorded from one county in England (Sussex) and one in Wales (Merioneth), but there are more records from Scotland. Aphis tormentillae has been recorded from most of Europe and from Russia.
Biology & Ecology:
The tormentil aphid may be overlooked, even by experienced aphidologists, because of the small size both of individuals and populations, and lack of ant attendance (Stroyan, 1984). We have only found it in one location - on the Dundreggan estate in Inverness-shire, Scotland. The host tormentil (Potentilla erecta) was common, and we found Aphis tormentillae on them on three occasions. We found most aphids on the leaf base and on the developing leaves (see picture below).
They are also found on the flowers of Potentilla erecta, often on the undersides of the bracts (see picture below).
They may even be found inside the flowers, where they remain even after petals have fallen (see picture below).
Other aphids on same host: