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Hyperomyzus picridis

Oxtongue aphid

On this page: Identification & Distribution  Biology & Ecology 

Identification & Distribution:

Adult apterae of Hyperomyzus picridis are shining pale yellow-green to dark green. The dorsum has variably developed brownish dorsal intersegmental markings as shown in picture below. The partially sclerotic dorsum distinguishes Hyperomyzus picridis from the related Hyperomyzus lactucae  which has the dorsum entirely membranous. The fused last two rostral segments (RIV+V) are 1.45-1.8 times longer than the second segment of the hind tarsus (HTII). The siphunculi and cauda are dusky. The siphunculi are 1.5-1.6 times longer than the long slender cauda, with the swollen part of the siphunculi about twice as thick as the narrow basal part. The body length of Hyperomyzus picridis aptera is 2.0-2.8 mm.

The Hyperomyzus picridis alate has a dark green abdomen with blackish green dorsal markings, mainly consisting of more or less unbroken cross bars (we suspect the pale green colour of the alate shown below is because it has recently moulted to the adult stage). There are numerous secondary rhinaria on the antennae with 55-95 on the third antennal segment, 12-34 on the fourth, and 0-6 on the fifth.

Hyperomyzus picridis host alternates from the primary host of alpine currant (Ribes alpinum) where it causes slight leaf curl to various members of the Asteraceae (Picris, Crepis and Rhagadiolus stellatus). Oviparae and winged males appear in October. Hyperomyzus picridis is widespread in Britain and Europe.

 

Biology & Ecology:

The most remarkable aspect of the ecology of Hyperomyzus picridis is the extraordinary plant architecture that it lives amongst on Oxtongue (Picris echiodes) - numerous grapple-hook hairs that various authors describe as trapping a wide range of insects (see for example www.plantlives.com/docs/P/Picris_echiodes.pdf ). It is these hairs that give rise to the common name for the plant of Oxtongue. We have never come across an Oxtongue aphid trapped in these hairs - since Picris is their main food plant, we can assume they have evolved adequate means of avoidance - but it seems entirely possible that some predators and parasitoids may be trapped.

Several authors report the observation of Hille Ris Lambers (1949)  that colonies on Picris are usually fairly small and occur just beneath the inflorescences.

However, in several locations in Dorset and East Sussex we have observed large dense colonies of this aphid on both the stems and leaves of Picris (see above).

 

As regards natural enemies, Hyperomyzus picridis is attacked by both parasitic braconids (see above first) and a bright orange fungal Entomophthora (see above second).

Acknowledgements

We especially thank the UK Forestry Commission Bedgebury Pinetum  for their kind assistance, and permission to sample.

We have made provisional 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).

Useful weblinks 

References

  •  Hille Ris Lambers, D. (1949). Contributions to a monograph of the Aphididae of Europe. IV. Aulacorthum (part), Microlophium, Hyalopteroides, Idiopterus, Pentalonia, Amphorophora, Amphorosiphon, Wahlgreniella, Megoura, Megourella, Hyperomyzus, Nasonovia. Temminckia 8, 182-329.