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Genus Tuberculatus

Oak and chestnut aphids

Species Overview: Genus Tuberculatus  Tuberculatus annulatus   Tuberculatus borealis  

Genus Tuberculatus [Panaphidini]

Small greenish aphids characterized by having one or more tubercular abdominal spinal processes.

There are about 60 species of oak- and chestnut-feeding aphids in this genus. All viviparae and males are alate. The genus includes some well-defined subgenera of limited distribution; those detailed below represent Tuberculoides found in the western palaearctic.

 

Tuberculatus annulatus (Common oak aphid)

The winged viviparae are very variable in colour ranging from yellowish, greyish-green or pink to purple in summer. The antennae are pale apart from black bands at the tips of the segments. The terminal process of the sixth antennal segment of the antennae is 0.87-1.1 times the length of the base of that segment. Abdominal tergites 1-3 each have a pair of spinal processes, with those on tergite 3 particularly large (these processes are difficult to see on live specimens). The tarsi are black. The siphunculi are dark on the distal third or more. The body length of alates is 1.7-2.2 mm.

 

The common oak aphid is found on the undersides of leaves of oak (Quercus spp.), especially English oak (Quercus robur) and, less commonly, sessile oak (Quercus petraea). Winged males and wingless oviparae occur in October. It is distributed throughout Europe to Siberia and north-west China, and has been introduced to Australia, New Zealand, North and South America.

 

Tuberculatus borealis (Blue-green oak aphid)

Winged viviparae are pale blue-green, yellow mottled with green, or yellow, with blackish-banded antennae The terminal process of the sixth antennal segment of the antennae is 0.9-1.3 times the length of the base of that segment. Abdominal tergites 1- 4 each have a pair of spinal processes, but those on tergite 4 are sometimes very small (these processes are difficult to see on live specimens). The siphunculi are only apically dark (rarely over more than the distal half). The body length of alates is 1.9-2.3 mm.

The blue-green oak aphid is found on English oak (Quercus robur), more rarely on other oaks. It is found across northern Europe into western Russia and east to Iran. It has been introduced to North America.

Acknowledgements

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).

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