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Identification & Distribution:

Cinara acutirostris apterae are dark brown to pale bronze, with a pattern of dark markings and wax dust. The siphuncular cones are large, prominent and black. The body length is 2.6-3.6 mm.

The first image above shows an adult aptera Cinara acutirostris on a branch of Corsican pine in amongst the attendant ants. It has signs of the characteristic bronzy iridescence of the adult. The second image shows two alates (winged forms) of Cinara acutirostris. The alates are similar to the apterae, but have predominantly dark legs with pale areas closest to the body. The appearance of the species is very similar to Cinara pini  and in the past we provisionally assigned those found on Corsican Pine to Cinara acutirostris, and those found on Scots Pine to Cinara pini. Our recent microscopic examinations suggest this was justified.

The image above is a dorsal view of a Cinara acutirostris aptera in alcohol. Key identification features to distinguish Cinara acutirostris from Cinara pini are 1) the length of the first tarsal segment is 0.5 times or more the length of the second tarsal segment; 2) the combined length of the last two rostral segments (RIV+V) is 1.2 to 1.5 times the length of the second tarsal segment and 3) there are several rather long hairs up to 110 µm long between the siphuncular cones of Cinara acutirostris, whilst the longest on Cinara pini are only about 48 µm.

Oviparae are dark brown with white wax marks laterally on the dorsum. Males are small (around 2.7 mm) and wingless and have a slender body form.

Cinara acutirostris is found on twigs of Corsican Pine (Pinus nigra) and Stone Pine (Pinus pinea). Oviparae and males can be found in October, and the species overwinters as eggs laid on the needles. It is found in western, southern and central Europe, China, and introduced to Argentina. It is commonly classed as an invasive species because of its introduction to countries along with Corsican Pine.

 

Biology & Ecology:

Cinara acutirostris overwinters as eggs which are laid on the pine needles in October and November.

 

The first picture above shows several eggs of this species. Buchholz & Scheurer (2000)  showed that a period of frost (-5 to -15C) for several weeks produced a higher ratio of hatching fundatrices than a period of around 0C temperature. The eggs hatch in March and April to give young nymphs as shown in the second picture above. These aggregate in tight clusters on the branches.

This image shows a young nymph - note the (proportionally) very long rostrum held under the body. It has to be similar in length to the adult's rostrum since it occupies the same feeding site.

These clusters of young nymphs of Corsican pine aphid in early spring were tended (and vigorously defended) by southern wood ants (Formica rufa). At this time of year the ants seem to be unusually aggressive to intruders (in this case the photographer), presumably because the ants are hungry and keen to protect their honeydew supply immediately post-hibernation.

 

These two pictures show southern wood ants attending mature colonies of Corsican pine aphids in mid-summer. Binazzi & Scheurer (2009)  class Cinara acutirostris as one of those species where ant attendance is 'compulsory' (obligate), and we have never found this species unattended.

 

Damage and control

Infestations of Cinara acutirostris are reported to cause economic damage (Delfino & Binazzi, 2002 ). In Sussex extensive browning of the needles of Corsican Pine appeared to be associated with heavy infestations of his species, leading us to conclude (wrongly, it would seem) that the browning was feeding damage by this species.

The immediate cause of browning was red band needle blight of pine, caused by the fungus Mycosphaerella (=Dothiostroma) pini. This disease causes premature needle defoliation, loss in timber yield and sometimes tree mortality (Brown et al. 2003 ). The apparent association between browning and aphid infestation may reflect infected trees being more attractive to aphids or aphids having a role in spreading the fungus between trees. Alternatively of course the observed association may have arisen by simple chance!

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

  •  Binazzi, A. & Scheurer, S. (2009). Atlas of the honeydew producing conifer aphids of Europe. Aracne. 132 pp. Introduction 

  •  Brown, A. et al. (2003). Red Band Needle Blight of Pine. Forestry Commission Information Note. Full text 

  •  Buchholz, S. & Scheurer, S. (2000). The influence of the length of frosty periods on emergence of fundatrices of selected Cinarinae (Sternorrhyncha, Lachnidae). Entomologica Brasiliensia 22, 143-147. Abstract 

  •  Delfino, M.A. & Binazzi, A. (2002). Áfidos de coníferos en la Argentina (Hemiptera: Aphididae). Rev. Soc. Entomol. Argent. 61 (3-4), 27-36.