Pleotrichophorus knowltoni Corpuz-Raros and Cook 1974
Creators: name: Stekolshchikov, Andrey V.
name: Khruleva, Olga A.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Aphidomorpha
Aphididae
Pleotrichophorus
Pleotrichophorus knowltoni

description: Pleotrichophorus knowltoni Corpuz-Raros and Cook, 1974
(Figs. 66–73, Tabl. 7)
Material. 1 fund., No. 10197, ChD, 7 km S Pevek, N 69о 38' N, E 170о 15' E, rubble-loam steep southern slope of the hill with spotty forb-semishrub-dryad vegetation, 21.vi.2011; 3 fund., No. 10198, ChD, 1 km N Pevek, N 69о 42', E 170о 21', petty dry mountain terrace with forb-sedge-dryad spotty vegetation, 1.vii.2011, sweeping; 2 fund., No. 10199, ChD, 20 km NE Pevek, the lower course of the Apapel’gin river, 69о 48' N, 170о 39' E., the burrow of ground squirrel with Artemisia sp., 5.vii.2011, sweeping; 6 fund., 1 apt., No. 10200, ChD, 1 km N Pevek, N 69о 42', E 170о 21', dry hillock with forb-wormwood-herb vegetation, 7.vii.2011, sweeping; 5 fund., No. 10201, ChD, 1 km N Pevek, N 69о 42', E 170о 21', dry mountain terrace with forb-wormwood-moss vegetation, 7.vii.2011, sweeping; 2 fund., No. 10202, ChD, 20 km NE Pevek, the lower course of the Apapel’gin river, 69о 48' N, 170о 39' E., hillock with equisetum-wormwood-forb vegetation, 22.vii.2011, sweeping; 1 ovip. and 1 male, No 10275, Ber, 6.viii.2012, Artemisia tilesii.
Comments. This species was described by Corpuz-Raros and Cook (1974) based on 1 apterous viviparous and 6 oviparous females from Alaska (Umiat). Other morphs of this species are not previously known. The following describes the fundatrix and the male collected in Chukotka. In the description the fundatrix is examined in more detail, and for the male, only differences from the fundatrix are specified.
Description. Fundatrix. Body elliptical, 1.7–2.2 (1.8–2.0) times as long as its width. Coloration of living specimens unknown. Cleared specimens with dark brown ultimate rostral segment and tarsi, brown 6th antennal segments and apices of 5th antennal segments, and light brown tibiae; all other body parts pale, no sclerites or maculae present on thorax and abdomen. Surface of head smooth or slightly wrinkled, except antennal tubercles, which on inner and ventral side have sparse large pointed spinules or short rows of such spinules; surface of dorsal side of thorax and abdominal tergites I–IV smooth or slightly wrinkled, of abdominal tergites V–VII with short rows of pointed spinules which on tergite VIII partially fuse to form short scales; surface of ventral side of thorax with small pointed spinules sometimes forming reticulate cells and surface of ventral side of abdomen with long rows of small pointed spinules sometimes forming strongly stretched reticulate cells. Setae on dorsal surface of thorax and abdomen widely expanded, fan-, mushroom- or funnel-shaped, on ventral surface pointed or finely pointed, setae on margins of body change from fan-shaped setae (situated near dorsum) to weakly capitate, blunt or pointed (situated near ventral side). Paired or sometimes unpaired marginal tubercles were present on prothorax and abdominal segments II–V, and often also on meso- and methothorax; total number of marginal tubercles on whole body 5–14 (7.7–12.2). Marginal tubercles not large (medial diameter of siphunculus 1.2–3.0 times as long as width of the largest marginal tubercle), protuberant from semicircular up to papilliform, diameter of tubercles 0.6– 4.0 times as long as high. Unpaired or rarely paired spinal tubercles were present on abdominal tergite VIII and sometimes on tergite VII; total number of spinal tubercles on whole body 1–3 (0.8). Head with weak traces of Fundatrix Male Number of samples / specimens 6/ 17 1/1
Length of body 2175–2681 (2275–2681) 1827 Length of antenna 2433–2722 (2481–2673) -
Length of antenna / length of body 1.05–1.18 (1.09) -
HFem length 628–872 (664–866) 721–746 length / length of body 0.27–0.33 (0.27–0.32) 0.39–0.41 length / W Head 1.24–1.66 (1.28–1.65) 1.45–1.50 HTib length 1105–1587 (1179–1576) 1274–1299 length / length of body 0.48–0.59 (0.48–0.59) 0.70–0.71 W Head 513–561 (521–561) 497
Setae on head occipital length 43–56 (44–50) 53
length / Ant3 AD 1.36–2.20 (1.45–1.86) 1.91
frontal length 46–58 (48–54) 58
length / Ant3 AD 1.50–2.30 (1.58–2.02) 2.09 on Ant1 number 5–8 (5.3–6.6) 7
length 20–30 (22–28) 28–30 on Ant3 number 11–19 (12.5–17.2) 15–16
length 18–20 (19) 18–19
length / Ant3 AD 0.58–0.80 (0.58–0.76) 0.64–0.68 on AntLB number 2–4 (3.0–4.0) -
length / AntLB AD 0.71–1.09 (0.88–1.00) -
length of ventral seta on HTr / BD HFem 0.68–1.47 (0.72–0.94) 0.67 on HFem length of dorsal 21–30 (23–28) 25–28
longest ventral 30–51 (37–46) 35–41
dorso-apical 15–21 (18) 20–23 on HTib longest dorsal 35–51 (38–51) 43–51
longest dorsal / mid-diameter of HTib 0.97–1.38 (1.12–1.33) 1.13–1.25 number on 2HT dorsal 1–2 (1.0–2.0) 2–3
ventral 2–4 (3.1–4.0) 4–6
on TerIII number of spinal and marginal 107–149 (120.7–135.0) 59
spinal length 33–44 (34–41) 35
length / Ant3 AD 1.09–1.70 (1.09–1.45) 1.27
marginal length 33–43 (36–41) 43
length / Ant3 AD 1.09–1.56 (1.18–1.51) 1.55
ventral length 46–66 (54–65) 51
length / Ant3 AD 1.82–2.60 (1.88–2.38) 1.82 number on TerVI between siphunculi 28–48 (31.7–39.0) 20
on TerVIII number 18–24 (19.7–24.0) 18
length 43–61 (48–59) 56
length / Ant3 AD 1.55–2.20 (1.67–1.91) 2.00 number on subgenital plate on anterior half 3–11 (6.7–11.0) -
along the hind margin 7–15 (9.7–13.0) -
......continued on the next page epicranial coronal suture. Frontal tubercles well developed, antennal tubercles rather high, divergent, median tubercle not high, but clearly marked. Setae on dorsal side of head widely expanded, fan-shaped, on ventral side fan-shaped, capitate or blunt. Antennae 6-segmented, 1st and 2nd antennal segments with sparse short scales, 3rd– 6th segments with large ones. Third antennal segment with 1–4 (1.3–3.5) secondary rhinaria located near base of segment, 4th and 5th segments without rhinaria; secondary rhinaria are round or oval, weakly protuberant. Antennae with blunt or pointed setae. Rostrum reaching mesothorax. Ultimate rostral segment stiletto-shaped with concave margins, needle-tipped. 2.04–2.86 (2.22–2.86) times as long as its basal width. Legs long, setae on legs blunt, weakly capitate or rarely pointed. Chaetotaxy of first tarsal segments 3, 3, 3, very rarely first tarsal segments with 2 setae. Arms of mesosternal furca connected by wide base. Spiracles reniform, peritremes on abdominal sternites I and II separated by a distance greater than diameter of peritreme. Siphunculi long, almost cylindrical, gradually tapering towards apex, often slightly curved outwards, with small but distinct flange, sometimes slightly widened at apex. Surface of siphunculi strongly imbricated, covered by rough scales, which are sometimes formed from partially fused large pointed spinules. Subgenital plate heart-shaped, rounded anteriorly and angular posteriorly, with blunt, weakly capitate or pointed setae. Setae on anal plate finely pointed. Cauda elongated triangular, sometimes almost finger-shaped, with rounded apex and long finely pointed setae.
Male. Single specimen with damaged antennae. Apterous. Body elongate-elliptical, 2.4 times as long as its width. The living specimen white with row of small green maculae along body margins and dark antennae. Cleared specimens with dark brown 3rd and 4th antennal segments except base of 3rd (5th and 6th antennal segments are absent) and intersegmental maculae, with brown apices of tibiae and tarsi, with light-brown legs (except apices of tibiae and tarsi) and apices of siphunculi, all other body parts pale, any sclerites absent on segments of thorax and abdomen. Setae on abdominal tergite VIII blunt, pointed or weakly capitate. Paired marginal tubercles present on abdominal segments II–IV (total number of marginal tubercles on whole body 8), spinal tubercles absent. Head without traces of epicranial coronal suture. Frontal median tubercle low, weakly marked. Setae on ventral side blunt or pointed. First and second antennal segments with very rare short scales and spinules. Third antennal segment with 37–46 secondary rhinaria spaced evenly along the segment, 4th segment with 22 rhinaria. Ultimate rostral segment 1.96 times as long as its basal width. Setae on legs blunt or pointed, rarely weakly capitate.
Peritremes on abdominal segments I and II continuous and fused. Surface of siphunculi strongly imbricated, covered by rough scales and large pointed spinules. Cauda triangular.
Biology. In the vicinity of Pevek Pleotrichophorus knowltoni was the most numerous aphid species collected in the few studied localities. Most specimens were collected in situations where Artemisia spp. were the predominant plant cover, as well as in zoogenic meadows. The host plant of aphids collected by sweeping in the vicinity of Pevek is unknown. In the vicinity of the village of Beringovsky the aphids were found in a colony of Macrosiphoniella (Asterobium) jaroslavi sp. nov. (No 10273) on Artemisia tilesii Ledeb.
Pleotrichophorus tuberculatus sp. nov. (Figs. 74–90, Tabl. 8)
Type material. Holotype: apterous viviparous female, No. 10272, slide No. 1, “ Pleotrichophorus tuberculatus sp. nov., 6.viii.2012, Chukotka Autonomous Okrug, Anadyrskiy District, near village of Beringovskiy, Artemisia tilesii Ledeb., on apices of soots, upper and lower surfaces of leaves and on stems, leg. A.V. Stekolshchikov”. Paratypes: 1 fund., No. 10203, ChD, 1 km south of Pevek, N 69° 40', E 170° 16', dampish rubble-loam, northeastern slope of hill with semishrubs (draft willow, dryad, cassiope)-moss vegetation, 1.vii.2011, sweeping; 2 apt., No. 10204, ChD, 1 km north of Pevek, N 69° 42', E 170° 21', dry rubble-loam southern slope with thinned steppificated forb-legume-herb vegetation, 18.vii.2011, sweeping; 13 apt., 2 ovip. and 3 males, No. 10272, from the same locality, data and host-plant as holotype; 6 apt., 1 al., 47 ovip. and 4 males, No. 10272- 9.VIII, 9– 10.viii.2012, from the same locality, data and host-plant as holotype, but reared in laboratory conditions.
Etymology. The name tuberculatus (Latin) refers to the presence of well-developed marginal tubercles.
Description. Fundatrix. Body elliptical. Colour of living specimen unknown. Head and 1st–3rd antennal segments of cleared specimen entirely brown (except base of 3rd segment). Thoracic and abdominal dorsum with weakly sclerotized, almost invisible bands. Paired marginal tubercles present on pro-, meso- and methathorax and on abdominal segments II–V; total number of marginal tubercles on whole body 16. Spinal tubercles absent. Setae on coxae blunt or pointed. Peritremes on abdominal sternites I and II separated by a distance greater than diameter of peritreme. Subgenital plate with pointed, blunt or weakly fan-shaped setae.
Apterous viviparous female. Body elliptical or elongated-elliptical, 1.7–2.1 (1.9–2.0) times as long as its width. The living specimens dirty brown-yellow with intensive wax pulverulence on dorsal and ventral sides; antennae pale brown with dark apices of 3rd and 4th segments and dark 5th–6th segments, legs pale, femora grey, apices of tibiae and tarsi dark, siphunculi dark, cauda dark-brown or dark-grey. Cleared specimens with antennae gradually darkening to the apex from brown to dark brown (usually apices of 3rd and 4th segment dark brown and 6th segment entirely dark brown); head brown with dark brown anterior half; ultimate rostral segment pale-brown, sclerites at bases of coxae, coxae, and tarsi brown or dark brown, trochanters, femora and tibiae pale-brown, tibiae often with more-or-less dark apices; tergites of thorax and abdomen with dark brown intersegmental maculae and brown, pale-brown or very pale brown bands, sclerites and peritremes; bands on abdominal tergites VI–VIII always darker than the bands on the thorax and anterior abdominal tergites; siphunculi, subgenital and anal plates and cauda brown. Thoracic and abdominal dorsum with more-or-less sclerotized broad transverse bands, which on metathorax and abdominal segments I–IV do not reach the margin of tergite and peritremes, and divide on lateral margins into separate weakly sclerotized sclerites situated between bands and marginal sclerites; marginal sclerites on abdominal segment I–IV small and very weakly sclerotized, almost invisible; marginal sclerites on segments V– VI very large and fused with each other and bands on these segments so that the siphunculi are completely surrounded by large sclerites and often entirely fused with them at their bases; marginal sclerites on segment VII very small. Surface of head, dorsal side of thorax and abdominal tergites I–III smooth or slightly wrinkled, of abdominal tergites IV–V with sparse pointed spinules, which on tergites VI–VII are grouped in short rows, and on tergite VIII are partially fused to form short scales. Ventral surface of thorax smooth or with small pointed spinules, sometimes forming cells and ventral surface of abdomen with long rows of small pointed spinules sometimes forming strongly stretched reticulate cells. Setae on dorsal surface of thorax and abdomen widely expanded, fan-, mushroom- or funnel-shaped, on ventral surface finely pointed or pointed; setae on margins of body vary from fanshaped (situated near dorsum) to weakly capitate, blunt or pointed (situated near ventral side). Paired or rarely unpaired marginal tubercles were almost always present on prothorax and abdominal segments I–VI, often on Fundatrix Apterous viviparous Alate viviparous females Males Oviparous females
females
Number of samples / specimens 1/1 3/ 22 1/1 1/ 7 2/22 on head occipital length 39 36–50 (43) 34 39–47 (42) 39–50 (45)
length / Ant3 AD 1.30–1.44 1.14–1.76 (1.46) 1.15 1.44–2.00 (1.73) 1.24–1.70 (1.55)
frontal length 50 42–59 (44–53) 53 44–50 (49) 50–62 (55)
length / Ant3 AD 1.70–1.89 1.47–2.11 (1.62–1.79) 1.80 1.67–2.13 (1.87) 1.71–2.11 (1.89)
on Ant1 number 6–7 5–8 (6.0–6.8) 5–6 5–7 (6.4) 5–8 (6.2)
length 21–27 21–30 (26) 22–27 24–36 (30) 24–39 (30) on Ant3 number 9 9–15 (10.7–12.6) 11–12 11–16 (13.6) 10–16 (12.5)
length 15 15–18 (16) 18 16–21 (18) 15–21 (18)
length / Ant3 AD 0.50 0.48–0.65 (0.56) 0.60 0.58–0.88 (0.68) 0.50–0.74 (0.62)
on AntLB number 2 3–4 (3.0–3.8) 3 2–4 (3.6) 2–4 (3.8)
length / AntLB AD 0.86 0.57–1.00 (0.78) 0.92 0.77–1.00 (0.83) 0.62–0.92 (0.81) length of ventral seta on HTr / BD HFem 0.78–0.79 0.67–0.86 (0.76) 0.55–0.69 0.42–0.83 (0.69) 0.64–0.91 (0.78) on HFem length of longest dorsal 24–25 21–30 (26) 27 21–33 (25) 24–44 (29)
ventral 27–33 27–47 (35–43) 33–39 36–44 (39) 36–47 (43)
dorso-apical 15–18 15–21 (17–19) 18–21 15–21 (19) 15–21 (18) on HTib longest dorsal 44–47 44–53 (48) 39–42 36–47 (40) 44–56 (50)
longest dorsal / mid-diameter of HTib 1.23–1.36 1.03–1.33 (1.18–1.28) 0.96–1.08 0.80–1.15 (1.00) 1.00–1.36 (1.16)
number on 2HT dorsal 2 1–3 (2.0) 2 1–3 (2.0) 2
ventral 2–3 2–4 (3.2–4.0) 4 3–5 (4.0) 3–4 (3.7)
on TerIII number of spinal and marginal 137 95–184 (108.0–151.0) 54 57–85 (69.7) 120–155 (138)
spinal length 36 30–42 (36) 24 33–39 (36) 36–53 (45)
length / Ant3 AD 1.20–1.33 1.00–1.44 (1.18–1.35) 0.80 1.22–1.63 (1.38) 1.20–1.89 (1.56)
…… continued on the next page Fundatrix Apterous viviparous Alate viviparous Males Oviparous females females females
Setae On TerIII marginal length 30 30–39 (33) 27 30–39 (33) 30–47 (39) length / Ant3 AD 1.00–1.11 1.00–1.33 (1.14) 0.90 1.11–1.44 (1.25) 1.00–1.67 (1.37) ventral length 65 50–80 (59–74) 71 56–68 (61) 62–83 (73) abdominal segment VII and unpaired marginal tubercle was rarely present on metathorax; total number of marginal tubercles on whole body 11–16 (12.0–14.7). Marginal tubercles often relatively large (medial diameter of siphunculus 0.9–1.7 times as long as width of the largest marginal tubercle), protuberant from semicircular up to papilliform, diameter of tubercles 1.0–3.0 times as long as high. Unpaired or paired spinal tubercles were often present on abdominal tergites VII and VIII and sometimes unpaired spinal tubercles present on tergite IV–VI; total number of spinal tubercles on whole body 1–7 (2.4–3.0). Head sometimes with weak traces of epicranial coronal suture. Frontal tubercles well developed, antennal tubercles rather high, divergent, median tubercle low but clearly marked. Setae on dorsal side of head widely expanded, fan-, mushroom- or funnel-shaped, on ventral side fanshaped, capitate or blunt. Antennae 6-segmented, 1st and 2nd antennal segments smooth dorsally and with sparse short scales on inner and ventral sides, 3rd–6th segments with large ones which are hardly visible on 3rd segment and well-defined on 5th–6th segments. Third antennal segment with 1–4 (1.8–2.7) secondary rhinaria located near base of segment, 4th and 5th segments without rhinaria; secondary rhinaria are round or oval, weakly protuberant. Antennae with blunt or weakly capitate setae. Rostrum reaching mesothorax. Ultimate rostral segment stilettoshaped with concave margins, needle-tipped, 2.11–2.61 (2.29–2.41) times as long as its basal width. Legs long, setae on coxae and tarsi pointed, on trochanters, femora and tibiae blunt, weakly capitate or rarely pointed. Chaetotaxy of first tarsal segments 3, 3, 3. Arms of mesosternal furca connected by wide base. Spiracles reniform, peritremes on abdominal sternites I and II fused or separated by a distance less than diameter of peritreme. Siphunculi relatively short, widened at base, then almost cylindrical, slightly curved into S-shape or outwards, with very small and indistinct flange. Surface of siphunculi strongly imbricated, covered by rough scales, sometimes formed by partially fused large pointed spinules. Subgenital plate oval, with pointed or blunt setae. Setae on anal plate finely pointed. Cauda elongate triangular, sometimes almost finger-shaped (with widened base and then with almost parallel margins), with rounded apex and long finely pointed setae.
Measurements of holotype. Body—2343×1314, antenna—1933: III—563×25 (in the middle), IV—415, V— 366, VI—153+726; hind femur—640, hind tibia—1128; siphunculus—166×33 (in the middle); cauda—293×166 (at base) ×139 (before base). For more biometric data see Table 8.
Alate viviparous female. Body elongate-oval, 2.5 times as long as its width. The living specimen dirty brownyellow with dark head, thorax, antennae, femora (except at bases), apices of tibiae, tarsi, and siphunculi, cauda dark-grey. Cleared specimen with dark brown head, thorax, antennae and intersegmental maculae, with brown coxae, trochanters, femora, apices of tibiae, tarsi, marginal sclerites, peritremes, siphunculi, subgenital and anal plates and cauda, with light-brown tibiae (except apices) and sclerites and bands on tergites of abdomen. Abdominal dorsum with groups of sclerites on abdominal tergites I–IV near central line of body, short transverse bands on tergites V–VI, broad transverse bands on tergites VII–VIII, small marginal sclerites on segments I, V and VII, large marginal sclerites on segments II–IV and VI, dark intersegmental maculae on segments I–VI and peritremes; sclerites on tergites I–IV partially fused; siphunculi situated on the marginal sclerites of segment VI (closer to anterior margin of sclerite) and completely fused with it basally. Two marginal tubercles present on prothorax and abdominal segments II–VI and one tubercle present on segment I; total number of marginal tubercles on whole body is 13. One spinal tubercle present on each of abdominal tergites VII and VIII. Head without traces of epicranial coronal suture. Third antennal segment with 14–15 secondary rhinaria spaced evenly along the segment, 4th and 5th segments without rhinaria; secondary rhinaria are round, relatively large (with internal diameter 10–19 Μm), weakly projecting, with external diameter 4.5–8.5 times as long as high of rhinaria. Ultimate rostral segment 2.67 times as long as its basal width. Setae on femora blunt or pointed. Peritremes on abdominal sternites I and II separated by a distance less than diameter of peritreme. Cauda finger-shaped, with widened base and rounded apex.
Male. Apterous. Body spindle-shaped, wide in the middle of abdomen (III–IV segments) and gradually narrowing to the head and end of the abdomen, 2.2–2.5 (2.3) times as long as its width. The living specimens dark brown with wax pulverulence; head, antennae, legs (except bases of femora), siphunculi and cauda all dark brown. Cleared specimens with dark brown head, antennae, legs (except bases of femora), bands, sclerites and peritremes on segments of thorax and abdomen, intersegmental maculae, anal plate, siphunculi and cauda; tibiae and parts of femora with small pale maculae at bases of setae so that the tibiae appear spotty. Sclerotization on thoracic and abdominal dorsum as in apterous viviparous female but more intense; abdominal sternites II–VII with sclerites on margins which on sternites VI–VII are fused and forming bands that are interrupted in the midline. Marginal tubercles almost always present on all segments of thorax, and on abdominal segments I–VI, and sometimes on VII; total number of marginal tubercles on whole body 16–19 (17.7). Spinal tubercles always present on abdominal tergite VII (paired in one specimen); most specimens also had a single spinal tubercle on VIII and some had one on VI; total number of spinal tubercles on whole body 1–3 (2.1). Head without traces of epicranial coronal suture. Third antennal segment with 21–34 (25.9) secondary rhinaria spaced evenly along the segment, 4th segment with 13–21 (18.0) and 5th with 10–17 (13.9) rhinaria. Cauda elongate triangular, with pointed apex.
Oviparous female. Body elliptical, 1.8–2.0 (1.9) times as long as its width. The living specimens reddish brown with wax pulverulence; antennae pale brown with dark apices of 3rd and 4th segments and dark 5th–6th segments, legs pale, femora light-grey, tarsi dark, siphunculi grey, cauda dark. Cleared specimens as in apterous viviparous females but slightly paler. Sclerotization on thoracic and abdominal dorsum much paler than that of apterous viviparous females, sometimes on thorax and anterior segments of abdomen very light-brown, almost invisible; metathorax and abdominal tergites I–III or I–IV with sclerites sometimes fused with each other and forming very fragmented bands; marginal sclerites on segment V not large and not fused with marginal sclerite on segment VI so that the siphunculi are fused basally only with the latter sclerite. Marginal tubercles almost always present on prothorax and on abdominal segments I–VI, and sometimes on meso- and metathorax, and segment VII; total number of marginal tubercles on whole body 12–17 (14.5). Spinal tubercles almost always present on abdominal tergites VII and VIII, and one tubercle present on tergite V in 5% of specimens; total number of spinal tubercles on whole body 1–4 (3.0). Rostrum reaching meso- or metathorax. Ultimate rostral segment 2.04–2.85 (2.40) times as long as its basal width. Setae on femora and tibiae blunt, pointed or weakly capitate. Subgenital plate oval, monotonously sclerotized, without dividing into two lobes. Cauda elongated triangular, sometimes almost linguiform with wide rounded apex. Hind tibiae markedly swollen in basal third, with 29–59 (46.8) round or oval pheromone plates, most of them located in the swollen part.
Distribution. Known only from Chukotka AO: Chaunskiy District, near Pevek; Anadyrskiy District, near village of Beringovskiy.
Biology. Monoecious, holocyclic. One fundatrix and two apterae viviparous females of the new species were collected by sweeping near Pevek on 1 July 2011 and 18 July 2011, respectively. Aphids were collected on the slopes of two hills in the most contrasting habitats—one relatively cold and the other one of the warmest.
A colony of this species consisting of apterous viviparous females, males, oviparous females, apteroid and alatoid nymphs was found in the vicinity of the village of Beringovskiy on upper and lower sides of apical leaves and on apices of shoots of Artemisia tilesii on 6 August 2012. Apteroid and alatoid nymphs were transferred to plants in laboratory conditions, where on 9–10 August 2012 an alate viviparous female and several more apterous viviparous females, males and oviparous females were reared.
Systematic relationships. Only two species of Pleotrichophorus — P. brevinectarius (Gillette et Palmer, 1933) and P. spatulavillus (Knowlton and Smith, 1936) —have siphunculi that are shorter than cauda in combination with a stiletto-shaped, needle-tipped ultimate rostral segment with concave margins that is shorter than 2nd segment of hind tarsus. From both those species P. tuberculatus differs by having dark head, antennae, coxae and cauda, as well as by the presence of sclerotized bands on tergites of thorax and abdomen and dark or dusky siphunculi. Comparing data from Corpuz-Raros and Cook (1974), Pleotrichophorus brevinectarius is also characterized by short siphunculi (70–130 Μm, compared with 126–201 Μm in P. tuberculatus), by the ratio of length of siphunculus to length of cauda (0.28–0.41, compared with 0.44–0.69 in P. tuberculatus), and by the ratio of length of processus terminalis to length of the base of the last antennal segment (5.67–7.55, compared with 4.30–5.32 in P. tuberculatus). Using data from both Corpuz-Raros and Cook (1974) and Knowlton and Smith (1936), Pleotrichophorus spatulavillus has a shorter ultimate rostral segment (110–130 Μm, compared with 127–148 Μm in P. tuberculatus), shorter cauda (190–260 Μm, compared with 240–314 Μm in P. tuberculatus) and shorter 2nd segment of hind tarsus (100–140 Μm, compared with 139–169 Μm in P. tuberculatus); the ratio of length of siphunculus to length of the cauda is 0.68–0.78 in P. spatulavillus and 0.44–0.69 in P. tuberculatus.
description: Published as part of Stekolshchikov, Andrey V. & Khruleva, Olga A., 2015, Contributions to the aphid fauna (Hemiptera, Aphidoidea) of Chukotka Autonomous Okrug with descriptions of five new species, pp. 1-44 in Zootaxa 4044 (1) on pages 32-41, DOI: 10.11646/zootaxa.4044.1.1, http://zenodo.org/record/289996