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Common pinyon-pine aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Adult apterae of Cinara edulis are cinnamon brown to dark brown to gun-metal or black (see pictures below of cinnamon brown form). There is a distinct medial abdominal wax stripe (rather faint on the specimens below), and light powdering elsewhere, especially just anterior to the siphunculi, but the wax may be rubbed off (cf. Cinara atra, which has no wax). The antenna have segment I, the distal tips of III-V, and all of VI dark. Antennal hairs are short and moderately sparse, with usually 0-2 secondary rhinaria. The rostrum is quite long, with moderate pigmentation, and its last segment (RIV) has 12-20 accessory hairs (cf. Cinara caliente, Cinara terminalis, Cinara wahtolca & Cinara anelia all of which have 4-8 accessory hairs on RIV). All the femora are lightly pigmented, with a gradual distal darkening over the entire length, and tibiae are dark at the apices; tarsi are dark. The hairs on the metatibiae are generally short and quite dense, and bent at an acute angle. The abdominal dorsum is smooth, with sclerites only on segment VII (cf. Cinara caliente, Cinara terminalis, Cinara wahtolca & Cinara anelia, all of which usually have sclerites on both tergites VI & VII). The sclerites on tergite VII may be large and rectangular such they cover most of it, or reduced to small aggregations of hair-bearing scleroites.
The siphunculi (see pictures below) are usually clearly delimited and dark, but occasionally lightly pigmented, or with two levels of pigmentation. The siphuncular cones have 10-41 hairs scattered over their surface, and are much longer than those on abdominal tergite V. (cf. Cinara atra, whose siphuncular cones have 5-15 hairs located around the cone's basal edge, similar in size and shape to those on tergite V). Tergite VIII has hairs along the posterior edge only. The body length of adult Cinara edulis apterae is 2.5-4.0 mm.
The alate Cinara edulis is similar to the apterous vivipara, apart from three points: Antennal segments III, IV & V are light basally, gradually becoming much darker distally. The pale area on the metatibiae is reduced, sometimes to nonexistence. Most importantly there is no sclerotization on tergum VII.
Note: the variability of Cinara edulis has led to confusion both in its popular and scientific naming. For example Palmer (1952) called it the "Black and White Spotted Pinyon Pine Aphid", a name which Hottes (1960) described. as "hardly suitable" given its variability in waxing and colour". Using multivariate morphometric analysis, Favret & Voegtlin (2004) demonstrated that five of the species that Hottes had previously described (Cinara apacheca, Cinara metalica, Cinara pinata, Cinara pinona & Cinara rustica), are probably synonyms of Cinara edulis.
Cinara edulis is monoecious holocyclic on just two species of pine: the two-needle pinyon pine (Pinus edulis) and the single-leaf pinyon pine (Pinus monophylla). Cinara edulis are found in large colonies on bark of branches and older twigs, or on young tree-trunks, or feeding among needles on the younger branches of young healthy trees with greenish bark. Oviparae and apterous and/or alate males occur in September-October, eggs being laid along the needles. It can be very abundant and injurious to the tree. The species is found in the western states of the USA.
Other aphids on the same host
Cinara edulis has been recorded on 2 pine species (Pinus edulis, Pinus monophylla).