Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Giant larch aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host Damage & Control
Identification & Distribution
Apterae of Cinara kochiana are greyish-brown to lead grey or greyish-green (see first picture below), and are slightly wax powdered. The dorsum shows a distinct dark flecked patterning of scleroites and there is often a spinal stripe. The extraordinary long rostrum is held curving underneath the body (see third picture below). The fourth rostral segment (RIV) is 0.29-0.42 mm long and bears 21-34 hairs arranged in 4 longitudinal rows (cf. Cinara cuneomaculata, in which R IV is 0.15-0.25 mm long and bears 5-11 hairs arranged in 2 longitudinal rows). The legs are hairy and the hind tibiae are either entirely dark brown, or with a short slighly paler base (cf. Cinara cuneomaculata, which has the hind tibiae dark distally but pale basally for 0.3-0.4 of their length). The siphuncular cones are small and black. The body length of Cinara kochiana is 4.7-6.1 mm.
The alate (see second picture above) has white wax markings on the dorsum of the abdomen.
Cinara kochiana is found on various larch species, including Larix decidua. Most reports state it occurs in ant attended colonies in bark crevices on the lower part of the trunk or bases of older branches, or in midsummer on exposed roots. Oviparae and winged or wingless males occur in October-November and eggs laid in bark crevices. Durak (2014) notes that Cinara kochiana is one of only five out of about 200 Cinara species to have both winged and wingless males. Cinara kochiana has been reported from most parts of Europe except Spain and Portugal, but is considered rather rare. It occurs as a subspecies in Korea.
Biology & Ecology:
There have been few recent observations on this aphid, and we know of no detailed studies on the ecology of the giant larch aphid. Borowiak & Wilkaniec (2010) recorded the species in the latter part of October in Cytadela Park in Poland. We have only found this species twice, from July to October 2014 and in autumn 2020, both in a mixed forest in East Sussex, UK.
They occurred where the bark was shaded by other vegetation.
Contrary to most other reports, in 2014 we found colonies on the older lower side branches (about 2 cm diameter) of a rather young partially fallen larch tree. None was found on the trunk or exposed roots of the tree. The colonies contained a mixture of all ages and morphs including many adult apterae (see picture below). In 2020 we found several small colonies on branch ends 2-2.5 m above ground - but there was evidence of an earlier larger colony on the lower trunk.
The colonies were attended by large numbers of southern wood ants (Formica rufa).
Pontin (1960) found a heavily parasitized population on larch roots. Our observations also suggest that the presence of attending ants does not provide as good protection to the giant larch aphid from parasites and predators as for example in the case of Cinara piceicola. The picture below shows a parasitized aphid in the colony we found.
Predators were also present, in particular a syrphid larva (see below).
Graham Rotheray commented on this larva "This is an early stage larva that hasn't developed all the features I need to be certain of its identity. Only three genera have the upright projections along the body shown in the image, Didea, Eriozona and Megasyrphus. But which of these genera the larva belongs to I can't really tell. ... simply on the grounds of abundance, it is most likely to be a Didea". (18 Aug 2014)
Other aphids on same host:
Cinara kochiana have been recorded from 5 Larix species (Larix decidua, Larix gmelinii, Larix kaempferi, Larix kamtschatica, Larix sibirica).
Damage and control
Rozhkov & Mikhailova (1993) note that Cinara kochiana has been recorded as one of the aphid species damaging larch trees in coniferous forests polluted with fluorides in Eastern Siberia. However, its presence probably resulted from the already damaged state of the trees resulting from the fluoride pollution. Cinara kochiana is a rare species and ought probably be given protected status.