Hyadaphis passerinii

Identification & Distribution:

Hyadaphis passerinii apterae (see first picture below) are elongate and grayish green with a waxy bloom. The antennae and legs are black. The prosternum has a dark trapezoid sclerite, visible in clarified mounts, which is 2.7-3.6 times wider than long (cf. Hyadaphis foeniculi where the prosternal sclerite is 1.36-2.6 times wider than long). The siphunculi are black and slightly swollen, 0.85-1.15× the length of the black, elongate cauda (cf. Hyadaphis foeniculi whose siphunculi are 1.05-1.45 times the cauda length). The body length of Hyadaphis passerinii apterae is 1.3-2.3 mm.

N.B. The characteristics of some of the populations we have found appear to be intermediate between Hyadaphis passerinii and Hyadaphis foeniculi: Hence we cannot be certain of the identification. Some authorities only accord passerinii and foeniculi subspecific status.

In spring Hyadaphis passerinii colonies curl the leaves of honeysuckles upwards, especially common honeysuckle (Lonicera periclymenum) and perfoliate honeysuckle (Lonicera caprifolium). The honeysuckle aphid host alternates between its winter host (honeysuckles) and its summer host - umbellifers (Apiaceae) especially Daucus, Conium and Pastinaca, where they colonise the stems, leaves and flowers. The return migration is in autumn. Hyadaphis passerinii is found in Europe and the Middle East and parts of Asia. It has also been introduced to southern Africa, Australia and America.

Other aphids on same host:

Hyadaphis passerinii has been recorded from at least 24 Lonicera species.

• Blackman & Eastop list 7 species of aphid as feeding on common honeysuckle (Lonicera periclymenum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 5 as occurring in Britain: (Show British list).

• Blackman & Eastop list 6 species of aphid as feeding on perfoliate honeysuckle (Lonicera caprifolium) worldwide (Show World list). Of those aphids, Baker (2015) lists 2 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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