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Identification & Distribution:

Adult apterae of Aphis passeriniana (see first picture below) are mottled dull-green to dark-green in life, with a fairly marked wax bloom. The abdominal dorsum is wholly pale and membranous or, at most, with faint traces of dusky bands across tergites 7-8. The apical rostral segment (RIV+V) is conspicuously long and the second hind tarsal segment (HTII) is conspicuously short, giving a ratio of 1.54-2.02. Aphis passeriniana siphunculi range from pale to dark (see pictures of apterae below), and are tapering, rather long and stout. The siphunculi are 0.80 - 1.25 times the length of the relatively short and bluntly finger-shaped cauda. Hairs on the legs are rather short, mostly distinctly shorter than the least width of the hind tibiae. The body length of adult apterae ranges from 1.16-1.78 mm

The alates (see second picture above) have marginal and (conspicuous) postsiphuncular sclerites and bands across tergites 7-8. The micrographs below show an adult apterous Aphis passeriniana in alcohol, dorsal (first) and ventral (second).

The sage aphid lives up growing shoots, in curled leaves and among the flowers of Salvia species, especially Salvia officinalis (garden sage), but also Salvia splendens (scarlet-flowered sage) and Salvia verticillata (lilac sage). Aphis passeriniana does not host alternate. It is assumed to overwinter as eggs on sage, but sexual forms have not been described. The only previous British record of Aphis passeriniana was in 1955, in the University Botanic Garden in Cambridge, so our record appears to constitute the second known occurrence in Britain. This is mainly a southern European species with records from Germany, Italy, Spain, Switzerland, Bulgaria, Croatia, Hungary and Greece, as well as Iraq and Israel.

 

Biology & Ecology:

We came across this (in Britain) extremely rare aphid  in Spring 2016, when one of us spotted ant-activity on one shoot in a well-established patch of sage (used heavily for culinary purposes, in an East Sussex garden). The ants were attending a single colony of aphids: three adult apterae and several immatures. The aphids were identified as Aphis passeriniana, the sage aphid, only recorded once before in Britain in Cambridge by Stroyan (1957).  Some of the specimens in our colony had an orange-yellow hue.

Ant attendance was persistent as long as the colony was not disturbed.

However, any disturbance led to rapid departure of the ants with no attempt made by the ants to defend their wards.

There no alates present when we first found the colony in April. We established a colony on cut stems of sage, and alates were produced as food quality declined and aphid density increased.

There is very little published work on Aphis passeriniana apart from records of occurrence, mainly in southern Europe and Israel, and recently in Iraq (Ali et al., 2012 ) The exception is Corsi & Bottega (1999)  who made a study of the glandular hairs of Salvia officinalis and their defensive function against insects that feed on Salvia in Italy. Prominent amongst the latter was the aphid Aphis passeriniana. The aphids were most abundant in spring and during blooming, but were also present in autumn, on the under surface of leaves. There, however, they were nearly always impeded by the downy layer of non-glandular hairs and the secretions released by the glandular hairs. They were observed on the ribs and grooves of calyces of flower buds and open flowers, towards the base rather than the teeth. Here again movement of the aphids was prevented by the many long non-glandular hairs on the calyces of buds, and by the viscous secretions of the glandular hairs on calyces of flowers in full bloom. Some aphids were reported stuck in the viscous substances released when they triggered rupture of the cuticle. Similar defense mechanisms have been reported against aphids in certain Solanaceae (Gregory et al., 1986 ).

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).

Useful weblinks 

References

  •  Ali, H.B. et al. (2012). New records of aphids of the subfamily Aphidinae (Homoptera: Aphididae) infested herbaceous plants and shrubs for Iraqi aphid fauna. Advances in Bioresearch 3(4), 66-75. Full text 

  •  Corsi, C. & Bottega, S. (1999). Glandular hairs of Salvia officinalis: New data on morphology, localization and histochemistry in relation to function. Annals of Botany 84, 657-664. Full text 

  •  Gregory (1986). Insect defensive chemistry of potato glandular trichomes. pp 173-184 In: Juniper, B.E. & Southwood, T.R.E. (eds) Insect and the plant surface. Edward Arnold, London.

  •  Stroyan, H.L.G. (1957). Further additions to the British aphid fauna. Transactions of the Royal Entomological Society of London 109(2), 311-360. Abstract