Nasonovia pilosellae

Identification & Distribution:

Adult apterae of Nasonovia pilosellae are medium-sized yellowish-green to blackish, rather shiny aphids. There are dark intersegmental sclerites between each abdominal segment, as well as variable and usually ill-defined dorsal pigmentation of the abdomen. The ratio of the length of the terminal process of the last antennal segment to its base ranges from 5.7-8.0 (cf. Nasonovia ribisnigri in which the ratio of the length of the terminal process of the last antennal segment to its base ranges from 7.0-11.4). The secondary rhinaria on the third antennal segment spread out along one side of the segment (see micrograph below) (cf.Nasonovia ribisnigri where the secondary rhinaria on the third antennal segment tend to be concentrated on the basal part of the segment). The first segment of their hind tarsus has two hairs. Their siphunculi are cylindrical and rather long, with little or no apical reticulation The cauda of Nasonovia pilosellae is elongate and rather blunt finger-shaped. The body length of the Nasonovia pilosellae adult aptera is 1.2-2.5 mm.

Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.

The hawkweed aphid lives all year round on a few related species of hawkweed, namely the orange hawkweed (Pilosella aurantiaca), common hawkweed (Hieracium lachenalii) and the mouse-ear hawkweed (Hieracium pilosella).

Other aphids on same host:

Nasonovia pilosellae has been recorded from 7 Hieracium species, and 2 Pilosella species (Pilosella caespitosa, Pilosella officinarum).

• Blackman & Eastop list 13 species of aphid as feeding on orange hawkweed, fox-and-cubs (Pilosella aurantiaca = Hieracium aurantiacum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 11 as occurring in Britain (Show British list).

• Blackman & Eastop list 6 species of aphid as feeding on common hawkweed (Hieracium lachenalii = H. argillaceum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 4 as occurring in Britain (Show British list).

• 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).

Acknowledgements Our particular thanks to Roger Blackman for images of his clarified slide mounts. Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974), Stroyan (1977), Stroyan (1984), Blackman & Eastop (1984), Heie (1980-1995), Dixon & Thieme (2007) and Blackman (2010). We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

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Identification requests Nancy Davies, June 18, 2014, aphids I picked up some aphids on Pilosella officinarum (mouse ear hawkweed) in sand dunes the other day and wondered if you wouldn't mind having a look at them for me, im sure they are the same species on the head of the flower even though they are a mix of black and green and winged and un-winged. Would you be able to confirm their identification and whether they are all the same. Images copyright Nancy Davies, all rights reserved.     I also picked up one aphid that looked different, im afraid it died and might be a little squished! Bob, InfluentialPoints: Your green and black aphids are most probably Nasonovia pilosellae. Apterae are shining green to black. Body length 1.2-2.5 mm. On Hieracium spp. living in spring inside upwardly rolled leaves, later moving onto stems and flowers. Please note we cannot be certain of these identifications because the green aphid was out of focus, and the resolution was lacking. It is just possible they are Nasonovia compositellae ssp. nigra. The "slightly squished" green aphid was a 4th-instar alate, very possibly the same species.