Pterocomma groenlandicum Hille Ris Lambers, 1952

Khruleva, Olga A. & Stekolshchikov, Andrey V., 2019, Additions to the aphid fauna of Wrangel Island due to climate change with redescription of the oviparous female of Pterocomma groenlandicum Hille Ris Lambers, 1952 (Hemiptera, Aphidoidea), Zootaxa 4615 (3), pp. 511-528 : 514-518

Pterocomma groenlandicum Hille Ris Lambers, 1952

( Figs. 4–10 , Table 1)

During the summer of 2006, we collected on Wrangel Island the previously unknown fundatrix of Pterocomma groenlandicum . We also found one badly damaged specimen that we thought was probably an oviparous female ( Stekolshchikov & Khruleva 2014). Since at that time fundatrices of this species were unknown and the ovipara too damaged to authoritatively identify, the record of P. groenlandicum on Wrangel Island was tentative. In 2015, apterous and alate viviparae, oviparae, and alate males were collected. These morphs were identifiable as P. groenlandicum , corroborating the previous geographic record.

Material. The middle reaches of the Mamontovaya River: low sandy-pebble floodplain with sparse plant beds (71° 09.523 N, 179° 45.328 W), 4–23.vii.2015, pitfall trap, 1 apt.; dampish plots in the river valley covered with willow ( Salix reptans Rupr. ) and grass-moss community (71° 09.593 N, 179° 45.137 W); willow bushes (71° 09.778 N, 179° 45.443 W), Salix lanata L. ssp. richardsonii (Hook.) and Salix glauca L., 1–22.vii.2015, pitfall trap, 6 apt.; the same localities, 22–23.vii.2015, sweeping, 2 apt., 1 al., 8 males; the same localities, 5.viii.2015, sweeping, 1 apt., 2 ovip., 15 males; zoogenic glade with herb-grass cover above an uninhabited polar fox den, 29.vi–22.vii.2015, pitfall trap, 1 apt.; the same locality, 22.vii–5.viii.2015, pitfall trap, 1 apt.; the same locality, 5.viii.2015, sweeping, 1 male; dry loamy ridge with grass-legume-dryad cover, 22.vii.2015, sweeping, 1 apt.; loamy rubbly southwest-facing dry slope of a shallow ridge with patchy herb-sedge cover, 5.viii.2015, sweeping, 1 male. The upper reaches of the Neizvestnaya River: willow bushes with Salix lanata ssp. richardsonii in the river floodplain (71° 12.823 N, 179° 19.620 W), 8.vii.2015, sweeping, 3 apt.

Hille Ris Lambers (1960) published a brief description of the oviparous female of P. groenlandicum based on a single specimen from Greenland (Umanak, 3.viii.1951): “The ovipara, until now unknown, very much like the apterous viviparous female, but the hind tibiae very thick and with hundreds of tubercular pseudosensoria”. Later, Wojciechowski (2003) gave a somewhat more detailed description of the morph based on two specimens, also collected in Greenland (Schaffltenserdalen, 2.vii.1961, and Fraenkel’s Land, 22.viii.1977). For most of the characters, he indicated the following: “Other characters as in apterous viviparous female”. The exact nature of these characteristics of ovipara therefore remain undocumented. Three new specimens have allowed us to redescribe the ovipara of P. groenlandicum .

Table 1. Biometric data for oviparous female of Pterocomma groenlandicum Hille Ris Lambers, 1952 .

Oviparous female

Oviparous female

from Greenland (after

from Wrangel Island

Wojciechowski 2003) Number of samples/specimens 2/3 2/2

3314 – 3949 Length of body 2720 – 3660

(3587)

1740 – 1974 Length of antenna 1480 – 1700

(1857)

0.50 – 0.60 Length of antenna / length of body 0.45 – 0.65

(0.55)

1112 – 1132

length –

(1125) Hind 0.29 – 0.34 femur length / body length (0.32) –

length / head width across the compound eyes 1.57 – 1.60 –

1848 – 2010

length –

(1912) Hind tibia

0.51 – 0.57

length / body length –

(0.54) Head width across the compound eyes 707 –

117 – 147

length –

(135)

occipital

length / articular diameter of 3rd 3.29 – 4.46

–

antennal segment (3.99)

on head

104 – 142

length –

(121)

frontal

length / articular diameter of 3rd 3.15 – 4.31

–

antennal segment (3.56)

10 – 13

number –

(11.8)

on 1 st antennal segment

69 – 106

length –

(84)

number 4 –

on 2nd antennal segment 69 – 126

length –

(98)

16 – 28

number –

(22.5)

on 3rd antennal 81 – 147

length –

segment (108)

length / articular diameter of 3rd antennal 2.46 – 4.46

–

segment (3.19) Setae number on 5th antennal segment 5 – 13 –

(9.3)

long setae 2 –

number of 3 – 5

on base of last short setae –

(4.0)

antennal segment

length of longest setae / articular diameter of 2.12 – 4.22

–

last antennal segment (3.05)

length of ventral seta on hind trochanter / basal diameter of 0.89 – 1.34

–

hind femur (1.04)

127 – 140

dorsal –

(131)

length of 119 – 127

on hind femur ventral –

longest (123)

64 – 89

dorso-apical –

(76)

longest dorsal 122 – 124 –

on hind tibia longest dorsal / mid-diameter of the hind 1.23 – 136

–

tibia (1.28)

number on 2nd segment dorsal 2 –

of hind tarsus ventral 5 –

on abdominal 191 – 284

number of spinal and marginal –

tergite III (240)

114 – 147 length – (131) spinal length / articular diameter of 3rd 3.21 – 4.46 – antennal segment (3.86) 114 – 159 length – margi- (134) nal length / articular diameter of 3rd 3.46 – 4.85 – antennal segment (3.93) 89 – 152 length – (112) ventral length / articular diameter of 3rd 2.64 – 4.62 – antennal segment (3.29) 59 – 79 number on abdominal tergite VI between siphunculi – (69.7) 33 – 44 number – (39.0) on abdominal 132 – 177 length – tergite VIII (148) length / articular diameter of 3rd antennal 3.70 – 5.38 – segment (4.37) 66 – 97 on anterior half – number on subgenital (78.3) plate 22 – 53 along the hind margin – (40.3) 169 – 198 length of base 160 – 170 (185) Last 249 – 298 antennal length of processus terminalis 230 – 300 (273) segment 1.27 – 1.69 length of processsus terminalis / length of base 1.44 – 1.76 (1.49) 4 – 5 number of accessory setae – (4.3) 159 – 183 length 160 Ultimate (175) rostral head width across the compound eyes 0.26 – segment 0.90 – 0.94 length of 2nd segment of hind tarsus 0.80 – 0.89 length / (0.92) 0.90 – 0.94 length of base of last antennal segment 0.94 – 1.00 (0.92) 196 – 203 length 180 – 200 (200) 2nd segment of hind 4.53 – 4.65 maximum width – tarsus (4.58) length / head width across the compound eyes 0.28 – length of base of last antennal segment 1.00 – 1.01 1.13 – 1.18 278 – 340 length 250 – 260 (306) body length 0.08 – 0.09 0.07 – 0.09 3.25 – 5.36 width of siphunculus at base – Siphunculus (3.99) Length / 2.82 – 3.44 width of siphunculus at half length – (3.07) 0.49 – 0.55 length of 3rd antennal segment 0.58 (0.53) 185 – 201 length – (189) 0.69 – 0.76 Cauda length / basal width – (0.73) 34 – 49 number of setae – (43.0) 1.53 – 1.70 Length of siphunculus / length of cauda – (1.61)

Description. Oviparous female. Body elliptical, 1.7–1.9 times as long as wide. Colour in life unknown. Cleared specimen with 1 st antennal segments, 3rd–4th rostral segments, apices of femora and tibiae, 1 st segment of all tarsus and peritremes dark brown; head, 2nd–6th antennal segments, sclerites at bases of coxae, coxae, trochanters, femora and tibiae (except apices), tarsi, apices of siphunculi, subgenital and anal plates, and cauda brown; bands and sclerites on dorsum of thorax and abdomen, and siphunculi light brown. Thorax and abdomen with large sclerotized bands on pro-, meso- and metathorax, and abdominal tergites VI–VIII, with sclerites on abdominal tergite I and V, marginal sclerites on all segments of thorax and abdominal segments I–VII (one specimen with small sclerites on abdominal tergites II–IV). Sclerotized bands on metanotum and tergites VI–VIII interrupted in the middle, one specimen also with interrupted band on mesonotum; marginal sclerites sometimes small or divided into separate smaller sclerites; sclerotized band and marginal maculae on tergite VII fused only on one side in one specimen. Surface of head, dorsal side of thorax and abdominal tergites I–VII smooth, weakly wrinkled; tergite VIII with short rows of small pointed spinules; ventral side of thorax reticulate, contour of cells formed by flat small spinules; ventral side of abdomen with long rows of small spinules, sometimes forming strongly stretched cells. Setae on body and appendages long and finely pointed (with filiform apices), rarely only pointed. Marginal tubercles always present on one or both sides of prothorax and abdominal segments II–IV (one specimen with two tubercles on segment VII and one with one tubercle on segment I), in two individuals from Greenland, the marginal tubercles present only on prothorax ( Wojciechowski 2003). Marginal tubercles small, 11–30 µm in diameter (on prothorax — 13–25 µm in diameter), from flat to nipple-shaped. Spinal tubercles absent. Head with epicranial coronal suture more or less distinct. Frontal tubercles low, weakly marked. Antennae 6-segmented, without secondary rhinaria. Rostrum reaching meso- or metathorax. Ultimate rostral segment faintly narrowed to apex, almost cylindrical, blunt, 1.68–1.85 times as long as its basal width. Legs strong. Chaetotaxy of first tarsal segments 5, 5, 4 (one specimen with 4 setae on fore and middle tarsus on one side). Arms of mesosternal furca connected by wide sclerotized stem. Spiracles reniform. Peritremes on abdominal sternites I and II separated by a distance lesser than diameter of peritreme. Siphunculi vasiform, relatively short, thick, weakly but distinctly swollen (diameter of the swollen part 1.10–1.54 times the smallest diameter of the basal half), with clear narrowing before flange, weakly wrinkled, with imbrication only before flange. Subgenital plate oval. Cauda broadly rounded.

Measurements of one specimen (sample No. 11212 according to the catalog of the Zoological Institute, the Russian Academy of Science, slide No. 1). Body—3314×1782, antenna—1930: III—576×38 (in the middle), IV— 330, V—330, VI—196+249; hind femur—1112, hind tibia—1848; siphunculus—302×94 (in the middle); cauda— 185×234 (at base). For more biometric data see Table 1.

Biology. In 2006, Pterocomma groenlandicum species was collected in two areas of the warmest central part of the island. It was found mainly on moderately moist gentle hills with moss-willow-grass cover, less often in wet habitats with willow bushes in river valleys.Almost all the collected specimens were fundatrices collected from July 5 to July 21, 2006. In 2015, this species was also collected in the center of the island but, unlike in 2006, it was found in small numbers in moderately humid biotopes. Most specimens were collected in wet sites of river valleys with willow thickets (Fig. 11, 14). In 2015, fundatrices were not collected. The first apterous viviparous females were observed in July 8; males, apterous viviparae and one alate vivipara were collected in July 22–23. In early August, males predominated in the samples, and 2 oviparous females were also found at the same time.

Figures

FIGURES 4–10. Pterocomma groenlandicum Hille Ris Lambers, 1952, ovip. 4, body; 5, antenna; 6, ultimate segments of rostrum; 7, hind tibia; 8, hind tarsus; 9, siphunculus; 10, cauda.