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Lachnochaitophorus querceusShiny brown oak aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & DistributionAdult apterae of Lachnochaitophorus querceus (see first two pictures below) are dark brown to black, and are, as Granovsky (1933) expresses it, "almost shiny". Their antennae are dusky dark brown, segments I-IV lighter at the base, segments V & VI black. The antennae are densely hairy, with 7-15 hairs on the base of antennal segment VI. (cf. Neomsymydobius species, which have sparsely hairy antennae and 1-3 hairs on the base of antennal segment VI). The aptera has an almost complete dorsal shield from mesonotum to abdominal tergite VII (cf. Lachnochaitophorus obscurus in south-eastern USA, which has separate cross-bands on abdominal tergites I-VII). The siphunculi are truncate, dusky brown without a flange. The body length of adult Lachnochaitophorus querceus apterae is 1.7-1.9 mm. Young immatures have the anterior part of the body reddish (see second and third pictures below).
Images above by permission, copyright Claude Pilon, all rights reserved. Alatae of Lachnochaitophorus querceus (see two pictures below) are dark brown to black, with black abdominal cross-bands and wing veins broadly and heavily bordered with fuscous. The dark bordering of the wing veins can be seen most clearly in the first picture below which gives a dorsal view of an alate amongst the tending ants. The wing veins have borders not more than 0.10 mm across, the pigment of veins Cu1a and the media vein not coalescing at their bases (cf. Lachnochaitophorus obscurus in south-eastern USA, which has wing veins with borders up to 0.15 mm across, the pigment of veins Cu1a and media coalescing at their bases). The Lachnochaitophorus querceus alate has 4-8 (usually 5 or 6) secondary rhinaria on antennal segment III. Note: The alate in the second picture below is teneral so the wing vein borders are quite faint.
Images above by permission, copyright Claude Pilon, all rights reserved. Lachnochaitophorus querceus lives in small colonies, mainly on leaf petioles and young bark of tender one-year-old shoots, of northern red oak (Quercus rubra) and black oak (Quercus velutina). It has also been reported forming dense clusters on twigs and leaf petioles of pin oak (Quercus palustris). These aphids are closely attended by ants, usually Crematogaster lineolata. In many cases the ants construct shelters over the colonies consisting of bits of oak epidermis and mud, over the upper part of leaf petioles just at the base of the leaf blades (Granovsky, 1933). These 'tents' or 'sheds' keep the aphids dry in rainy weather, and conceal them from predators. Lachnochaitophorus querceus is monoecious holocyclic. In autumn it produces oviparae with swollen hind tibiae and a greatly extended posterior abdomen, and small apterous males. It is restricted to north-eastern USA and Canada (Quebec, Ontario). Other aphids on the same hostLachnochaitophorus querceus has been recorded from 4 species of oak (Quercus ilcifolia, Quercus palustris, Quercus rubra, Quercus velutina).
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