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Oxtongue aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host
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 green abdomen with blackish green dorsal markings, mainly consisting of more or less broken cross bars. 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).
Other aphids on same host:
Hyperomyzus picridis has been recorded on 9 Ribes species (including gooseberry, Ribes uva-crispa).
Blackman & Eastop list 14 species of aphid as feeding on alpine currant (Ribes alpinum) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).