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Tasmanian beech aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
The adult aptera of Sensoriaphis tasmaniae (see first picture below) has the head and prothorax dirty yellow and the abdomen olive-green. The antennae are 5-6 segmented. Antennal segments I & II are brown, segments III to the base of V are pale, and the rest of segments V and VI dark. The antennal terminal process is about 0.46 times the length of the base of antennal segment VI. The head & pronotum are fused, with only the front somewhat dark sclerotic. There are two pairs of rugose, finger-like marginal processes on both the mesothorax and metathorax, and one pair of marginal processes on all abdominal tergites except V (cf. Sensoriaphis nothofagi, which just has one pair of small marginal processes on abdominal segments VI & VII). Each marginal process has a capitate hair at its apex. Tergite VIII has a pair of spinal finger-like processes in addition to the marginal processes (cf. Sensoriaphis nothofagi, which just has a pair of spinal processes on tergite VIII). The siphunculi on abdominal tergite V are prominently developed cones, brown with a broad pale flange. The cauda is constricted to form a longish pear-shaped brown knob.
Images above by permission, copyright Kristi Ellingsen, all rights reserved.
Alatae of Sensoriaphis tasmaniae have the head and thorax brown; the abdomen green and the legs brown. Antennal segment III bears 9-16 secondary rhinaria. There is a dusky, spinulose or rugose area present dorso-marginally on all abdominal tergites except segment V, each bearing 2-4 hairs. Marginal processes are variously developed, but not so well as in apterous viviparous female; these processes are most strongly developed on abdominal tergites III and IV. Spinal processes on tergite VIII are conical to finger-like, each bearing 1, rarely 2, setae. The knob of the cauda is turnip-shaped, about 2 times its maximum width at base.
The Tasmanian beech aphid infests the young shoots of myrtle beech (Nothofagus cunninghamii). Carver & Martyn (1962) report that the population was at a low level during winter, but numbers increased markedly with the advent of spring; the species was still fairly common in early December, but by February none could be found. The aphids pictured above were found in late December. Sensoriaphis tasmaniae is only found in Tasmania.
Other aphids on the same host
Sensoriaphis tasmaniae has been found on only one species of Nothofagus (Nothofagus cunninghamii).
Blackman & Eastop list only 1 species of aphid as feeding on myrtle beech (Nothofagus cunninghamii) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists none as occurring in Britain (Show British list).