Adelges (Adelges) tardus (Dreyfus, 1888)

Albrecht, Anders Christian, 2017, Illustrated identification guide to the Nordic aphids feeding on Conifers (Pinophyta) (Insecta, Hemiptera, Sternorhyncha, Aphidomorpha), European Journal of Taxonomy 338, pp. 1-160 : 10-11

Adelges (Adelges) tardus (Dreyfus, 1888)

Figs 10–14

Diagnosis

Overwintering pseudofundatrix nymphs 0.3–0.4 mm, blackish with sparse, glossy grey, stiff, almost straight wax filaments. Al. gallicolae: 1–2 mm; ant. III longer than IV; glands (including premarginal) developed, blackish with reddish brown abdomen exuding abundant fine wax wool. They remain in the vicinity or their gall, laying eggs covered with abundant wax. Galls as in A. laricis , but gregarious, along with galls from preceding years, opening in August–September. Gall chambers not completely closed: nymphs can frequently be seen on the outer surface. Gallicolae blackish, secreting abundant wax. Anholocyclic on Picea . Usually on trees in rather open position: clearings, forest margins, solitary spruces and spruce hedges. Galls frequently intermixed with galls of Adelges abietis . Overwintering pseudofundatrices seem to prefer the surface of buds, not their bases as in A. abietis (according to my own records from Finland).

Recorded hosts

Pinaceae : Picea abies *, glauca , pungens , sitchensis .

Distribution

D F S.

A10 (A9) Overwintering larvae: Dorsal sclerites with groups of similar-sized ring-like wax pores. Al. gallicola with basal articulation of ant. IV and V narrower ................................................. ..................................... Adelges ( Gilletteella Börner, 1930 and Sacciphantes Curtis, 1844 )

Figures

Fig. 10. Adelges (Adelges) tardus (Dreyfus, 1888). Galls on Picea abies. A–B. Almost full-grown. C. Almost mature. D–E. Mature, first gallicolae have emerged. F–G. Fully opened galls. Scale bars: 10 mm.

Fig. 11. Adelges (Adelges) tardus (Dreyfus, 1888) on Picea abies. A. Mature, opened gall with alate gallicolae on surface. B–I. Gallicolae laying eggs on needles in vicinity of their mother gall. J–K. Gallicolae in vitro. Scale bars for E–K: 1 mm.

Fig. 12. Adelges (Adelges) tardus (Dreyfus, 1888). A–F. Hibernating pseudofundatrix nymphs on buds of Picea abies. Note the sparse, long, more or less straight wax filaments (most of them worn off, except in D–E). Often together with nymphs of A. (Sacciphantes) abietis (Linnaeus, 1758), whose wax filaments are dense, flattened and strongly curled (the specimen to the right in B). The nymphs usually hibernate on the surface of the bud, whereas those of A. abietis prefer bud bases and axils. G. Hibernating nymphs, which are easiest to find in the vicinity of the previous summer’s galls.

Fig. 13. A–C. Adelges (Adelges) tardus (Dreyfus, 1888). Wax-covered pseudofundatrices at bases of developing galls on Picea abies. D. As A–C, but with the wax wool brushed off to expose the pseudofundatrix and her eggs.

Fig. 14. A–B. Developing galls of Adelges (Adelges) tardus (Dreyfus, 1888) on Picea abies, close to galls of A. (Sacciphantes) abietis (Linnaeus, 1758). C. Half-grown galls of A. tardus and A. abietis on the same twig. Note the tufts of protruding needles on the A. tardus galls, apparently due to interference from A. abietis. Scale bars: 10 mm.