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Brown larch aphidOn this page: Identification & Distribution Biology & Ecology: Life cycle Ant attendance Competition / coexistencee Natural enemies Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Cinara cuneomaculata are darkish brown to orange-reddish (see two pictures below), sometimes with dark green segmental markings. There is usually a dusting of greyish wax powder on the ventral surface of adults which may (rarely) extend as stripes on to the dorsum of the abdomen. Small, hair-bearing sclerites are absent (cf. Cinara laricis, which has numerous small black hair-bearing sclerites). The fourth rostral segment is from 0.15 to 0.25 mm in length (cf. Cinara kochiana, which has the fourth rostral segment 0.29-0.42 mm long). The siphuncular cones are small. The hind hind tibiae are dark distally but pale basally for 0.3-0.4 of their length (cf. Cinara kochiana, which has the hind tibiae either entirely dark brown, or with a short slighly paler base). The femora are mostly dark brown but paler proximally. The body length of Cinara cuneomaculata apterae is 2.4-4.6 mm.
Beware: Cinara cuneomaculata often forms mixed species colonies with Cinara laricis, as illustrated below.
Alatae (not pictured) are similarly coloured to the apterae. The micrographs below show adult apterae of Cinara cuneomaculata, dorsal and ventral.
Cinara cuneomaculata feed on young twigs and shoots of larch (Larix spp.). The egg laying females (oviparae) occur in October. They are found in Europe excluding Scandinavia and the Iberian peninsula; also in parts of Asia.
Biology & Ecology
The eggs laid on larch the previous year hatch in spring to give the fundatrices. As with Cinara acutirostris, 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 where the temperature is around 0°C.
The species forms small colonies on the young twigs and shoots of larch. The earliest we have found them on larch is early May. The picture below shows an adult aptera in early May with a little greyish wax powder extending as a stripe on to the dorsum of the abdomen.
These two images taken in July and September shows groups of young nymphs feeding on the branches. As with many other species, they cluster together when feeding to create a sink effect which improves the flow of nutrients.
Alatae seem to be unusually scarce, although Carter & Maslen, 1982 report finding them in a brief period between June to mid-July, both on the host and in suction traps. We have found what appear to be brachypterous forms late in the year.
Carter & Maslen, 1982 reported finding dark brown oviparae with darker sclerotized blotches and no pericaudal wax ring. The latter observation appears to be in error as we have regularly found light brown/reddish-brown oviparae of this species with marked pericaudal wax rings.
As well as feeding in aggregations of its own species, Cinara cuneomaculata can often be found in multispecies aggregations.
The aphid in the centre of the picture above with a pericaudal wax ring is an ovipara of Cinara cuneomaculata, whilst the other aphids around the ovipara belong to a different species of larch aphid - Cinara laricis.
Binazzi & Scheurer (2009) report that this species is independent from ant attendance, but we have found that ants are usually present.
In the picture above, taken in late August, a southern wood ant (Formica rufa) is stroking an old viviparous female to promote honeydew production. The copious honeydew crystallizes to Lärchenmanne which is highly regarded by beekeepers in central Europe.
In the image above the ant has taken up its defensive posture with its abdomen swung forward ready to spray formic acid against any perceived threat.
We have so far not observed any predation on this species (possibly because of protection by the ants), but at least one species of parasitoid is often present. The first image shows a parasitized aphid known as a 'mummy'.
The adult braconid parasitoid which emerged from this mummy is shown below.
Our identification is a little uncertain but this appears to be Pauesia pini, a species recorded as parasitizing both of the larch species of Cinara (Wiaçkowski et al., 2001.)
Other aphids on same host:
Blackman & Eastop list 29 species of aphid as feeding on Larches (Larix species) worldwide (of which 15 are Adelges, and 9 are Cinara), and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 7 as occurring in Britain (Show British list).
Damage and control
We are not aware of any work quantifying the effects of infestation by this species on the timber yield of larch, but it seems safe to assume that foresters regard this aphid as harmful, and beekepers see it as beneficial! Börner & Franz (1956) reported that dense 'overpopulated' colonies caused a local yellowing of the foliage.