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Dusky-spotted caragana aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
All adult viviparae of Therioaphis tenera are alate. Immatures (see first picture below) are pale yellow, unspotted and bear capitate dorsal hairs. Alate Therioaphis tenera (see second picture below) are yellowish. Abdominal tergites I-VII each bear 4 hairs, 1 pair spinal and 1 pair marginal (cf. Therioaphis trifolii, which has more than 4 hairs on each of abdominal tergites I-VII). These hairs arise mostly from unpigmented or lightly dusky tubercular bases, some with dark edging, giving a largely pale dorsum with incomplete rows of small dark spots (cf. Therioaphis riehmi, which has the hairs arising from pigmented tubercular bases, giving four longitudinal rows of completely dark sclerites on the dorsum). The siphunculi are pale. The body length of alate Therioaphis tenera is 1.7-2.2 mm.
Both images above by permission, copyright Claude Pilon, all rights reserved.
The first image below shows the typical dispersed pattern of immature Therioaphis tenera feeding on the leaf undersides. The second and third images show the reduced dorsal markings of this species.
There are two subspecies of Therioaphis tenera, one apparently has a specific host-plant association.
Therioaphis tenera feeds on Caragana spp.. Colonies can be found living dispersed on undersides of leaflets, mostly on lower branches. Fundatrices are present in June, and oviparae and alate males in late August-September. It is distributed through north and central Europe into Russia, Ukraine and Central Asia, and has been introduced to Quebec, Canada where the aphids pictured here were photographed.
Other aphids on the same host
Therioaphis tenera ssp. tenera has been recorded on 10 species of Caragana (Caragana arborescens, Caragana boisii, Caragana caragana, Caragana decorticans, Caragana frutex, Caragana fruticosa, Caragana jubata, Caragana pleiophylla, Caragana pumila, Caragana sinica). Therioaphis tenera ssp. frutex has only been recorded on Caragana frutex.