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Asian honeysuckle-knotgrass aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Trichosiphonaphis polygonifoliae are greenish brown. We only have pictures (assuming our identification is correct - see note below) of immature and mature alatae, which are reddish brown. The antennal and median frontal tubercles of Trichosiphonaphis polygonifoliae are weakly developed. The antennae are a little shorter than the body, with a terminal process that is at least 6 times as long as the base of antennal segment VI. The apical rostral segment is distinctly longer than the base of antennal segment VI. The siphunculi are paler on the middle part, a little constricted near the tip, with a swollen apical rim, and 2.5-3.5 times the caudal length (cf. Trichosiphonaphis corticis & Trichosiphonaphis alpestris, which both have siphunculi completely flangeless, and 3.6-5.0 times the cauda). On the basal two-thirds of the siphunculi there are 8-16 minute hairs, at most only 5-11 µm long. The cauda is constricted on the distal part, with 6-9 hairs. The body length of adult Trichosiphonaphis polygonifoliae apterae is 1.8-2.5 mm. in length.
Note: The lack of any adult apterae in the colony, and the rather low resolution of the pictures, made identification difficult, in particular we could not check for the (diagnostic) presence of minute hairs on the siphunculi. However, the host, feeding site (stems), lack of wax and the shape of the siphunculi strongly indicate Trichosiphonaphis polygonifoliae.
Images above by permission, copyright Dr László Érsek, all rights reserved.
The alate Trichosiphonaphis polygonifoliae has the head, antennae and thorax black. The antennal tubercles are very short, slightly rounded, with one or 2 hairs. The antennae are a little shorter than body. The alate emigrant from the primary host has 16-46 oval or round secondary rhinaria on segment III, 0-16 on segment IV, and 0 on V. The alate sexupara returning from the secondary host has far more rhinaria, with 80-100 on III, 40-63 on IV, and 0-9 on V. The siphunculi are paler on the middle part, less imbricated on the distal half, and with some minute blunt hairs on the basal two-thirds. There are large marginal sclerites on tergites II-V & VII and a small one on VI; dorsal sclerites are present on tergites VII-VIII. The body length of adult Trichosiphonaphis polygonifoliae alatae is 1.8-2.0 mm.
Image above by permission, copyright Dr László Érsek, all rights reserved.
In spring Trichosiphonaphis polygonifoliae feed in colonies (see picture above) on twigs of honeysuckle (Lonicera species). They host alternate in June-July to roots of knotgrass (Persicaria and Polygonum spp.). Trichosiphonaphis polygonifoliae is native to east Asia (Japan, China, Korea, east Siberia), but it has been introduced to Europe and seems to be increasing its range. It has been recorded from France, Italy, Serbia, Turkey, Britain (in suction trap) and now (from this record) Hungary.
Other aphids on the same host
Trichosiphonaphis polygonifoliae has been recorded on 4 species of honeysuckle (Lonicera insularis, Lonicera japonica, Lonicera morrowii, Lonicera tatarica).
Trichosiphonaphis polygonifoliae is recorded on 3 Polygonum species (Polygonum cognatum, Polygonum senticosum, Polygonum thunbergi).
Trichosiphonaphis polygonifoliae is recorded on 4 Persicaria species (Persicaria amphibia, Persicaria hydropiper, Persicaria lapathifolia, Persicaria longiseta).