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Neosymydobius albasiphusWhite-cornicled oak aphidOn this page: Identification & Distribution Other aphids on the same hostIdentification & DistributionAdult apterae of Neosymydobius albasiphus (see pictures below) are shining black or brown with a pale spinal stripe. There is conspicuous white wax around the siphunculi and on the cauda. Their antennal tubercles are poorly developed. The antennae are pale with black annuli at the apices of the segments (cf. Neosymydobius neomexicanus in New Mexico, USA, which has antennal segments III-VI almost entirely dark). The terminal process is more than 0.5 times as long as the base of antennal segment VI (cf. most other Neosymydobius spp., which have the terminal process less than 0.4 times the base of that segment). The hairs on antennal segment III are slender, with the longest about 0.67 times the basal diameter of that segment. The apical rostral segment (RIV+V) has 4-6 accessory hairs. Each abdominal tergite has a transverse, pigmented sclerotic bar that may be broken in the middle on some segments (cf. most other Neosymydobius spp., which have no transverse abdominal bars, but only small sclerites). Each abdominal segment has one or more transverse rows of mostly long fine hairs dorsally and a cluster laterally. Lateral abdominal sclerites are also present on each segment. The fore- and mid-legs are very pale fuscous and the hind legs are dark brown apart from the tibial apices. The cauda is weakly knobbed, and the anal plate is deeply indented. The body length of adult Neosymydobius albasiphus apterae is 1.4-1.9 mm. Note: Neosymydobius canadensis Richards, 1965, was described by Richards (1965) as being very similar to Neosymydobius albasiphus. It differs in lacking the white waxy coating of the siphunculi (and cauda), in possessing somewhat longer hairs on antennal segment III, and in some aspects of larval chaetotaxy. Given its similarity in morphology, it was synonymized with Neosymydobius albasiphus by Remaudière (1982).
Images above copyright Ashley Bradford under a Creative Commons License. Alatae of Neosymydobius albasiphus (not pictured) are coloured similar to the apterae. The wings have dark costal veins, but other veins are not bordered. Neosymydobius albasiphus feeds on various Nearctic oak species including white oak (Quercus alba), bur oak (Quercus macrocarpa), swamp chestnut oak (Quercus michauxii), swamp Spanish oak (Quercus palustris) and post oak (Quercus stellata). Davis 1914 provided some interesting observations on its biology in Indiana, USA. In all cases the aphid was found on leaves near the leaf petiole, usually on the under leaf surface, and invariably attended by the ant, Crematogaster lineolata. In Virginia, USA, they had also been found tented over with mud on the upper side of the leaf. Oviparae and alate males occurred in September-October. Neosymydobius albasiphus is found in eastern USA and Canada. Other aphids on the same hostNeosymydobius albasiphus has been recorded on 6 species of oak (Quercus alba, Quercus macrocarpa, Quercus michauxii, Quercus palustris, Quercus prinus, Quercus stellata).
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