Acyrthosiphon boreale Hille Ris Lambers, 1952

Stekolshchikov, Andrey V. & Khruleva, Olga A., 2015, Contributions to the aphid fauna (Hemiptera, Aphidoidea) of Chukotka Autonomous Okrug with descriptions of five new species, Zootaxa 4044 (1), pp. 1-44 : 14-17

Acyrthosiphon boreale Hille Ris Lambers, 1952

( Figs. 26–33 , Tabl. 3 , 4 )

Material. 5 apt., No. 10327, ChD, 1 km south of Pevek, N 69° 40', E 170° 16', steep southern slope with tundrasteppe forb-sedge-dryad vegetation, 29.vi.2011, sweeping; 1 apt., No. 10328, ChD, 1 km south of Pevek, N 69° 40', E 170° 16', from the same locality as No. 10327, 11.vii.2011, sweeping; 15 apt., No. 10251, SSWBer, Potentilla palustris (L.) Scop., 17.vii.2012, on lower sides of leaves and pedicles near flowers; 2 apt. and imm., No. 10268, SSWBer, Potentilla palustris , 27.vii.2012, on lower sides of leaves, pedicles and flowers (imm. were transferred to plants in laboratory conditions, where 1 al. and 2 apt. were obtained 29.vii.2012 (No. 10268- 29.VII), and 2 apt., 1 ovip. and 4 males were obtained 4–6.viii.2012 (No. 10268- 4.VIII )).

Comments. This species is known from northern Europe, United Kingdom, Greenland and Canada (Baffin Island) and also, possibly, from Switzerland, Poland, Czech Republic, Hungary, Lithuania, Ukraine, Kazakhstan and east Siberia; these latter records need verification ( Blackman and Eastop, 2015). In the vicinity of Pevek this species was collected only at a single location on a steep southern slope with tundra-steppe vegetation. In the vicinity of Beringovskiy it was one of the commonest aphid species. Apterous viviparous females from Chukotka slightly differ from those from elsewhere: their ultimate rostral segment, processus terminalis and siphunculi are shorter; they have on average a few more setae on the appendages and secondary rhinaria on the 3rd antennal segment ( Tabl. 3 ). However, these differences are not taxonomically significant and can be attributed to geographical variability.

The oviparous female of this species has not been described previously; for males, only the number of setae on the ultimate rostral segment and the number of secondary rhinaria on antennal segments ( Stroyan, 1964), or just the number of rhinaria ( Blackman, 2010) have been recorded. Below more detailed descriptions are given of apterous males, and the first description of the oviparous female. The oviparous female is examined in more detail, and for the male only differences from the oviparous female are specified.

longest dorsal / mid-diameter of HTib 1.00–1.20 (1.08) 0.71–0.78 number on 2HT dorsal 3–5 (3.6) 3–6

ventral 6–9 (7.8) 5–8

on TerIII number of spinal and marginal 11–15 (12.0) 12

spinal length 15–20 (18) 15

length / Ant3 AD 0.48–0.62 (0.55) 0.50

marginal length 18–23 (20) 16

length / Ant3 AD 0.56–0.69 (0.62) 0.54

ventral length 38–48 (44) 33

length / Ant3 AD 1.14–1.52 (1.37) 1.08

number on TerVI between siphunculi 4–5 (4.3) 5

on TerVIII number 5–7 (6.0) 7

length 41–48 (44) 41

length / Ant3 AD 1.23–1.58 (1.37) 1.33

number on subgenital on anterior half – 15

plate along the hind margin – 31

......continued on the next page Description. Male. Apterous. Body spindle-shaped, 2.2–2.5 (2.3) times as long as its width. Color of other body parts of living specimens as in oviparous female. Cleared specimens have very pale brown sclerites and bands on abdominal tergites I–VIII and siphunculi (only slightly darker than body), pale brown head, antennae and legs, brown apex of 5th antennal segment, whole 6th antennal segment (but with processus terminalis gradually lightening towards apex), ultimate rostral segment, apices of tibiae and tarsi, and pairs of elongated brown spots on abdominal tergites I–V. Abdomen with very pale brown, almost undiscernible sclerites and short bands on tergites I–VI (situated on central line of body), large cross-bands on tergites VI–VIII, postsiphuncular sclerites, marginal maculae and peritremes on segments I–VII; the band on tergite VII can be divided into separate sclerites or fused with marginal maculae. Marginal tubercles always present on prothorax and abdominal segments I–V and only one tubercle absent on segment I in three specimens and on segment V in one specimen; total number of marginal tubercles on whole body 10–12 (11.0). Medial diameter of siphunculus 2.3–3.0 times as long as width of the largest marginal tubercle. Head with or without more-or-less distinct traces of epicranial coronal suture. Third antennal segment with 34–48 (38.6) secondary rhinaria, 4th segment with 7–19 (14.3) and 5th segment with 13–19 (16.4) secondary rhinaria (data of Stroyan (1964) for two specimens from Iceland: III—32 – 36, IV—8–19, V—8–14, and one specimen from England (Hertfordshire): III—43 –45, IV—0–4, V—6–10; data of Blackman (2010): III—28– 42, IV—5–19, V—11–13); secondary rhinaria are round, weakly protruberant, with external diameter 3.0–8.0 times as long as their height, spaced evenly along the segment. Peritremes on abdominal sternites I and II fused.

Oviparous female. Body spindle-shaped, 2.1 times as long as its width. The living specimens pale yellow, slightly green, antennae pale brown, apex of 5th segment and 6th antennal segment dark, legs pale with dark apices of tibiae and tarsi, siphunculi pale with dark grey apices, cauda pale; with sparse waxy pulverulence on ventral side. Cleared specimens pale with very pale brown (only slightly darker than body) head, antennae, legs, and siphunculi, and pale brown apex of 5th antennal segment and whole 6th antennal segment with processus terminalis gradually lightening towards apex, ultimate rostral segment, apices of tibiae and tarsi also pale brown; any sclerites or maculae absent on segments of thorax and abdomen. Dorsal surface of head, dorsal and ventral sides of thorax, and of abdominal tergites I–V smooth, sometimes slightly wrinkled, of abdominal tergites VI–VII with the long rows of small pointed spinules, which on tergites VIII partially fuse to form scales; surface of ventral side of head smooth with sparse small spinules, which sometimes forming short rows, of inner side of antennal tubercles with short scales; 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 relatively short (longer on tergites VI–VIII), weakly capitate or blunt; setae on ventral surface of thorax and abdomen pointed or slightly blunt. Two marginal tubercles present on prothorax and on abdominal segments III–V, and one tubercle present on abdominal segment I; total number of marginal tubercles on whole body 9. Marginal tubercles not large (medial diameter of siphunculus 3.3–3.5 times as long as width of the largest marginal tubercle), flat or weakly protuberant. Spinal tubercles absent. Head with weak traces of epicranial coronal suture. Frontal tubercles moderately developed, antennal tubercles high, divergent, median tubercle indistinct, almost invisible. Setae on head blunt or weakly capitate. Antennae 6-segmented, without secondary rhinaria, 1st and 2nd antennal segments slightly wrinkled, almost smooth, with short sparse scales outward, 3rd–6th segments with large scales which almost invisible on 3rd segment and well-defined on 5–6th segments. Antennae with blunt or weakly capitate setae. Rostrum reaching metathorax. Ultimate rostral segment elongated wedge-shaped. Legs long, setae on trochanters, femora and tibiae blunt or weakly capitate, on coxae and apices of tibiae pointed or, rarely, blunt. Chaetotaxy of first tarsal segments 3, 3, 3. Arms of mesosternal furca connected by wide base. Peritremes on abdominal sternites I and II separated by a distance less than diameter of peritreme, spiracles reniform. Siphunculi long, slightly curved outwards, with distinct flange, with broad base, then almost cylindrical and slightly widened before flange, with imbrication consisting of small scales. Subgenital plate oval, with pointed or blunt setae. Setae on anal plate finely pointed. Cauda elongated triangular with rounded apex and long finely pointed setae. Hind tibiae not greatly swollen in basal half, with 125–126 round pheromone plates distributed over almost the entire length of the tibia, but more of them located in the basal half.

Figures

FIGURES 26 – 33. Acyrthosiphon boreale Hille Ris Lambers, 1952, male and ovip. 26, body of ovip.; 27, frons of ovip.; 28, antenna of ovip.; 29, hind tarsus of ovip.; 30, siphunculus of male; 31, siphunculus of ovip.; 32, cauda of male; 33, cauda of ovip.

Tables

TABLE 3. Morphological comparison of apterous viviparous females of Acyrthosiphon boreale Hille Ris Lambers, 1952 from different populations (after Heie, 1994, Hille Ris Lambers, 1952 and Stroyan, 1964).

Greenland	Iceland	North of Europe	England	Switzerland	Chukotka
PT / AntLB 4.75–5.66	4.78–5.38	4.60–6.00	3.96–6.62	4.60–5.81	4.21–5.75
Number of secondary rhinaria on 2–9 Ant3	2–8	2–9	1–25	2–12	3–15
Number of accessory setae on URS 6–8	7–12	6–11	8–15	9–17	8–16
Length of URS / length of 2HT 1.06	1.03	0.90–1.10	0.99–1.38	1.00–1.33	0.76–0.91
Number of setae on CAUD 7–9	-	7–11	-	-	7–12
Length of SIPH / length of CAUD 1.90–2.26	-	1.90–2.30	-	-	1.66–2.18

TABLE 4. Biometric data for males and oviparous female of Acyrthosiphon boreale Hille Ris Lambers, 1952.

Number of samples / specimens	Males 1/4	Oviparous females 1/1
Length of body Length of antenna	1969–2137 (2044) 3122–3332 (3197)	2254 2531–2534
Length of antenna / length of body HFem length	1.52–1.62 (1.57) 919–995 (954)	1.12 792
length / length of body length / W Head	0.44–0.49 (0.47) 1.84–1.99 (1.93)	0.35 1.58
HTib length length / length of body	1665–1797 (1737) 0.80–0.91 (0.85)	1492–1502 0.66–0.67
W Head Depth of frontal sinus / width between antennal bases	486–501 (494) 0.22–0.31 (0.27)	501 0.27
Setae on head occipital length length / Ant3 AD	20–28 (23) 0.64–0.85 (0.72)	25 0.83
frontal length	20–35 (27)	28
length / Ant3 AD on Ant1 number	0.64–1.08 (0.84) 6–7 (6.4)	0.92 6–7
length on Ant3 number	20–28 (23) 12–17 (15.4)	20–22 18–19
length length / Ant3 AD	16–18 (18) 0.50–0.58 (0.54)	15 0.50
on AntLB number length / AntLB AD	2–4 (3.0) 0.71–1.00 (0.87)	3–6 0.40–0.71
length of ventral seta on HTr / BD HFem on HFem length of longest dorsal	0.40–0.50 (0.46) 15–25 (21)	0.41–0.42 20–23
ventral dorso-apical	25–30 (27) 18–23 (20)	28–30 18
on HTib longest dorsal	38–46 (42)	38–46