Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Dark periphyllus aphidIdentification & Distribution Biology & Ecology Damage & Control
Identification & Distribution:The Periphyllus obscurus aptera is rather small and blackish green. The terminal process of the antenna is 3.2-6.9 times the length of the base of the last antennal segment. The siphunculi are dark and only about as long as the basal width. The hind tibiae are more or less pale without a contrasting dark base and distal section. The cauda is rounded with a constriction near its base and is more than half as long as its basal width. The body length is 1.8-2.6 mm.
The dark periphyllus aphid is found in ant-attended colonies on young shoots, leaf petioles and undersides of leaves of Field Maple (Acer campestre). Aestivating nymphs are apparently not produced. The oviparous female has been described. Periphyllus obscurus is found in central and western Europe.
This shows an aptera of Periphyllus obscurus. It is a rather uncommon species in the UK, although not apparently so in parts of Europe. It is best distinguished from Periphyllus testudinaceus by the pale hind tibiae (more clearly visible on the aptera in the last picture on this page) together with the fact that all stages are present through the summer with no aestivating nymphs.
Biology & Ecology:
This picture shows a colony of Periphyllus obscurus in early August. Note that apterae and nymphs of several stages are present together - at this time of year, Periphyllus testudinaceus would normally only be present as aestivating nymphs. The very young nymphs of Periphyllus obscurus are green, whilst older nymphs are brownish.
Periphyllus obscurus is usually (or always) attended by ants as shown in this picture where it was vigorously protected by southern wood ants (Formica rufa). Quinet (1997) recorded it as being attended by Lasius fuliginosus.
Damage and control
The species seems to be rather uncommon in UK so is unlikely to reach pest numbers. In Europe, however, it is clearly more abundant and has been recorded as a pest species on ornamental trees and shrubs by Ripka (1999) in Hungary. The rather small colony in the picture below was being predated by a syrphid larva.