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Corsican pine aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host Damage & Control
Identification & Distribution:
Cinara acutirostris apterae are dark brown to pale bronze, with a pattern of dark markings, a pale grey longitudinal line of wax dust and lateral wax patches on the dorsum. The appearance of the species is very similar to Cinara pini so we give several discriminating characteristics. 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 (cf. Cinara pini which has the length of RIV+V less than 1.2 times the length of the second tarsal segment). Also the length of RV is more than 3 times its basal width (cf. Cinara pini where the length of RV is less than 3 times its basal width). The siphuncular cones of Cinara acutirostris are large, prominent and black. There are several rather long hairs, up to 100 µm long, between the siphuncular cones (cf. Cinara pini where the longest hairs are only 6-50 µm long.) The body length of adult Cinara acutirostris apterae is 2.6-4.1 mm.
Cinara acutirostris alates are similar to their apterae, but have predominantly dark legs with pale areas closest to the body. The micrographs below are dorsal views of a Cinara acutirostris aptera and alate in alcohol.
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. Cinara acutirostris 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 -15°C) for several weeks produced a higher ratio of hatching fundatrices than a period of around zero degrees. 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 immediately post-hibernation are hungry and keen to protect their honeydew supply.
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.
Other aphids on same host:
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 may have a role in spreading the fungus between trees. Alternatively of course the observed association may have arisen by simple chance!