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Bedstraw shoot aphidOn this page: Identification & Distribution Biology & Ecology: Life cycle Ant attendance Associations Natural enemies Other aphids on the same host
Identification & Distribution
Adult apterae of Staegeriella necopinata are yellowish-green or greyish-green aphids (see two pictures below), powdered ventrally with grey wax. The grey siphunculi are short and truncate, have a small but distinct apical flange, and are distinctly constricted below that flange. The siphunculi are 0.5-0.8 times as long as the grey finger-shaped cauda. The body length of adult Staegeriella necopinata apterae is 1.3-2.2 mm.
Immature Staegeriella necopinata are greenish with more or less extensive wax powdering especially intersegmentally. The alate has similar short truncate siphunculi, rather pale marginal sclerite and no abdominal patch.
Staegeriella necopinata does not host alternate, but remains all year round on bedstraws, mainly yellow bedstraw (Galium verum). It feeds on the stem, growing shoot and flower. Oviparae and alate males occur in autumn, with overwintering in the egg stage. Staegeriella necopinata is found in throughout Europe, although it is rare in Britain.
Biology & Ecology
Staegeriella necopinata - the bedstraw shoot aphid - is one of several aphid species largely restricted to bedstraws. It appears to be rather rare in the British Isles with few recent records of its occurrence. Wood-Baker & Hopkins (2000) found the species in County Kerry, Ireland in 1997, and described the oviparae for the first time. Baker (2009) observed this species feeding in large numbers on the flowering heads of several Galium verum plants growing in unimproved grassland at Porthkerry Park, Barry, in Wales. We found it for the first time in 2018, in Malling Down Nature Reserve in East Sussex.
The main host of Staegeriella necopinata is lady's bedstraw (Galium verum, see picture above). Other aphid species specific to bedstraws include Aphis galiiscabri and Linosiphon galiophagum (both mainly on hedge bedstraw, Galium mollugo), Hydaphias mosana (found at the stem base of lady's bedstraw) and Hydaphias hofmanni (found on the roots of either bedstraw species).
Staegeriella necopinata is found up the stem and on the flowers of lady's bedstraw, but it especially favours the growing point (see picture above).
The immatures (see first picture above) are distinctive, with blue-grey wax intersegmentally. The adult (see second picture above) has no wax on the dorsum.
As the plant grows the colony extends from the growing point down the stem (see picture above).
Sexual forms develop in autumn - the picture above shows the alate male Staegeriella.
Staegeriella necopinata is not generally considered to be ant-attended, and none of the colonies we have found has been attended. However, Ozdemir et al. (2008) has recorded ant attendance of Staegeriella necopinata on Galium verum by the ants Plagiolepis pallescens and Plagiolepis vindobonensis in Ankara Province, Turkey.
Staegeriella necopinata can be found in close association with Myzus cerasi, a host alternating aphid species which uses Galium as its secondary host. The picture below shows an immature Myzus cerasi feeding beside an immature future alate male Staegeriella necopinata on the growing shoot of lady's bedstraw.
When this photo was taken (late September) the Myzus cerasi were producing alates (see fourth instar alatiform nymph below) which would migrate back to their primary host, cherry (Prunus cerasus).
We found no predators or parasitoids attacking the colonies we found on lady's bedstraw in East Sussex. Baker & Broad (2013) reported finding brown mummies of Staegeriella necopinata in Porthkerry Park, Barry in Wales. The parasitoid, Binodoxys brevicornis, proved to be a new species to Britain.
Other aphids on same host:
Staegeriella necopinata has been recorded on 9 Galium species: Galium aparine, Galium boreale, Galium ceratopodum, Galium glaucum, Galium intermedium, Galium lucidum, Galium mollugo, Galium rubrum and Galium verum.