header image
Siricidae (Hymenoptera: Symphyta: Siricoidea) of the Western Hemisphere
CJAI 21, July, 2012
doi: 10.3752/cjai.2012.21
Nathan M. Schiff, Henri Goulet, David R. Smith, Caroline Boudreault, A. Dan Wilson, and Brian E. Scheffler

Sirex abietinus Goulet, n. sp.

Fig. C4.1 (female habitus)
Fig. C4.2 (male habitus)
Fig. C4.4 (map)

Sirex juvencus race cyaneus Bradley, 1913: 14, (not S. cyaneus Fabricius, 1781: 419); accepted as subspecies by Ries 1951: 83, Middlekauff 1960: 65, Smith 1979: 126. This synonymy applies only to females from the Rocky Mountains and westward.
Sirex cyaneus Ries, 1951: 83 (not Fabricius, 1781: 419); Middlekauff 1960: 64, Smith 1979: 127. This synonymy applies only to females from the Rocky Mountains and westward.


Diagnostic Combination

Among females with a completely light reddish brown metafemur, short metatarsomere 2 (tarsomere 1.5 to 3.0 times as long as high), and long tarsal pad (pad 0.7–0.8 times as long as ventral length of tarsomere) [cyaneus, hispaniola, and nitidus], those of S. abietinus are recognized by the very small pits at the middle of the lancet (length 0.0–0.13 times as long as length of annulus), length of annulus 10 1.76–2.37 times as long as height of ovipositor (lance + lancet), and the lack of pits in basal 6–9 annuli of the ovipositor. Among males with a reddish brown metafemur and mainly black metatibia [cyaneus, nitidus, noctilio and varipes] those of S. abietinus are recognized by the completely light reddish brown mesotibia and mesotarsus, the generally larger pits on the gena and vertex (pit diameter 0.25–0.4 times lateral ocellus diameter), and the narrow pale spot at the base of the metatibia (spot extending slightly beyond minimum constricted portion and as long as or slightly longer than wide).

Adults of this species are extremely similar to those of S. cyaneus, but the range of S. abietinus is from the Rocky Mountains and westward.

Description

FEMALE

Color. Body, antenna and palps black with dark blue metallic reflections. Coxae black, femora, tibiae and tarsi light reddish brown (apical half of tarsomeres 5 occasionally darker but not dark brown or black, and femora black in one specimen from southern Yukon). Fore wing mainly clear, at most tinted light brown in apical third.

Head. Gena with pits 0.0–4.0 pit diameters apart; vertex especially on postocellar area with pits 0.0–2.0 pit diameters apart, and each pit diameter 0.15–0.25 times lateral ocellus diameter.

Thorax. Mesoscutum with coarse, net-like pits in median area. Metatarsomere 2 in lateral view 2.1–3.2 times as long as high, and its length about 1.0–1.2 times length of tarsomeres 3 + 4; tarsal pad 0.8–0.9 times as long as ventral length of tarsomere. Fore wing vein 3A absent.

Abdomen. Median basin of tergum 9 with basal width 0.65-1.2 times as long as median length, maximum width 1.1-1.4 times as long as median length, and median length 0.55-0.65 times cornus length (Fig. B2.87). Cornus in dorsal view usually long and thick, with edges straight and curved apically, its median length 1.2–1.4 as long as maximum width of abdomen at junction of terga 9 and 10 (Fig. B2.87). Sheath. Length 0.75–0.95 times fore wing length, basal section 0.75–1.0 times as long as apical section. Ovipositor. Lancet with 31–37 annuli (basal annuli weakly outlined); junction of basal and apical section of sheath aligned between 9th and 10th or 10th and 11th annuli, with 26–29 pits beginning with annuli 4–11 (Fig. C4.3). Pits near middle annuli or area at base of apical section of sheath 0.03–0.14 times as long as an annulus (pits gradually and markedly decreasing in size toward base), 0.15–0.4 times as high as lancet height in lateral view, and 1.0–1.7 times as long as high; annulus 10 length/ovipositor diameter (lance + lancet) 1.76–2.37 (based on 26 specimens) (Fig. B2.85). Last 4-6 annuli before teeth annuli as well as first tooth annulus with ridge on ventral edge of pit (Fig. C3.5). Edge of apical 6-8 annuli before teeth annuli extended as ridge to ventral edge of lancet (Fig. C3.5).

MALE

Color. Head, thorax and coxae black with dark blue metallic reflections. Coxae, metatibia (except extreme base), and metatarsomeres 1-3 black; femora, and tibiae and tarsus of fore and mid legs light reddish brown. Fore wing tinted light yellow. Abdomen with segments 1–3 (basomedian region from tergum 4 to as many as terga 4–7) black, segments 3–7 (excluding black median spot when present) light reddish brown, and sternum 9 light reddish brown rarely with some black at side.

Thorax. Metatibia 3.9-5.5 times as long as maximum width. Metatarsomere 1 in lateral view 3.1-3.4 times as long as maximum height.

Type Material

Holotype female (CNC), in perfect condition, labeled “Clearwater BC 20–VI–67” “66–6076–03 Abies lasiocarpa R’rd [reared] logs Coll [struck out]” [White label], “HOLOTYPE Sirex abietinus Goulet CNC No. 23907” [Red label]. Type locality: Canada, British Columbia, Clearwater.

Paratypes. 50 females and 10 males. CANADA. Alberta: Banff, 10.IX.1924 (1F, MTEC); Banff, 11,IX.1924 (1 F, MTEC). British Columbia: Atlin 22.VIII.1955 (1 F, CNC); Clearwater, 2.VIII, 3.VIII.1966, 31.V, 5.VI, 20.VI, 22.VI.1967, reared from Abies lasiocarpa (8F, 1M allotype [20.V], CNC); Forest Insect Survey 272, 6.VIII.1938 (1 F, CNC); Forest Insect Survey 393, 15.IX.1939 (1 F, CNC); Hope Mountains, 20.VIII.1931 (1 F; CNC); Lower Hazel Cr., 10.VIII (1 F, CNC); Lumberton 3.VIII.1935 (1 F, CNC); Mount Revelstoke, 6000’, 12.VIII.1923 (11 F, CNC); Quam Lake (1 F, CNC); Sarita River 2.VIII. 1946, 22.VII, 30.VII, 5.VIII..1948 (3 F, 3 M, CNC); Uslika Lake 5.VII, 20VII,1967, reared from Abies lasiocarpa (2 M, CNC); Uslika Lake 20.VII.1966, reared from Abies lasiocarpa (2 M, CNC); Mi 41, Uslika Lake Rd. 18.VI.1966, reared from Abies lasiocarpa (1 M, CNC); Vancouver, 18.VIII.1914 (1 F, CNC); Vancouver Island (1 F, CNC); Vernon, 30.VI, 5.VII.1965, reared from Abies lasiocarpa (3 F, CNC); White Pine Cr., 26.V, 3.VII.1967, reared from Abies lasiocarpa (2 M, CNC). Yukon Territory: Lake Laberge, 1929 (1 F, CNC); Whitehorse 27.VIII.1959 (1 F, CNC). USA. California: Napa Co., Angwin, 20.IX.1968 (1 F, USNM). Colorado: no data (1 F, USNM). Montana: Gallatin Co., Bozeman, 19.VIII.1984 (1F, MTEC); Rivali Co., Nezperce Mountain, VII.1923 (1F, MTEC). Nevada: Elko Co., Jarbidge, Hopk. U.S. 18677, 15.VIII.1929 (1 F, USNM). Oregon: Klamath Co., Crater Lake Nat. Park, Crater Springs (1 F, USNM); Sisters, 15.VII.1938, reared from Abies lasiocarpa, R. L. Furniss, Hopk. U. S. 31,766–S, barcode 00105829 (1 F, OSAC). Utah: Tabionia, 25.IX.1941, R. L. Furniss, barcode 00110916 (1 F, OSAC). Washington: Clear Lake, 24.II.1955, reared from Abies amabilis, cage 26, barcode and 00105775 (1 F, OSAC); Mount Rainier Nat. Park, Paradise Valley, Hopk. U.S. 4245a (1 F, USNM). Wyoming: Teton Co., Yellowstone Nat. Park, Old Faithful, 26.VIII.1925 (1 F, 2 M, USNM).

Taxonomic Notes

Sirex abietinus is a Nearctic species. Adults of this species are very similar to those of S. cyaneus, a Nearctic species. Sirex cyaneus should not be confused with the European “S. cyaneus”, a name incorrectly used in Europe for two European species that should be called S. torvus M. Harris (see chapter D. Additional Notes) and S. juvencus. The ovipositor of S. abietinus has no pits in basal 0.4, a character state that does not occur in either European species. Sirex abietinus is the western equivalent of the more eastern S. cyaneus. Sirex abietinus females have relatively long ovipositor annuli (value calculated only for annulus between pits 9 and 10) and, commonly, a thick and long cornus, and males have completely light reddish brown apical abdominal segments. Sirex cyaneus females have relatively short ovipositor annuli (value calculated only for annulus between pits 9 and 10) and a short cornus, and males (except in Alberta and perhaps Saskatchewan) have at least sterna 8 and 9 black (in most specimens, tergum 8 is completely black). The information from morphology and DNA barcoding shows a difference of almost 10.6% in the base pair number between S. abietinus and S. cyaneus. Clearly, the western populations (i.e., S. abietinus) are specifically distinct from S. cyaneus. The ranges of both species are allopatric. The two species have no known close relatives in Eurasia.

In western North America, this species is sympatric with S. nitidus and the pale femora form of S. californicus. In S. abietinus females, the pit size on the middle annuli of the ovipositor and the proportion of the length of the annulus between pits the 9 and 10 relative to the ovipositor diameter distinguish them from females of S. nitidus. In S. abietinus males (except specimens from Alberta and perhaps Saskatchewan) the middle leg color patterns distinguish them from S. nitidus males. Sirex abietinus females are easily distinguished from S. californicus females with pale femora by the long tarsal pad of metatarsomere 2, and the ovipositor pit size and shape at middle and base.

Though not yet within the range of S. noctilio, both sexes of S. abietinus are easily distinguished from S. noctilio by puncture size on the vertex and the pit development of the mesoscutum; females are easily separated by the long tarsal pad of metatarsomere 2 and the pit development near the middle of the ovipositor, and males by the reduced pale spot at the base of the metatibia.

Origin of Specific Epithet

This is an adjective derived from the genus name for the host tree, Abies, and abietinus means “of fir” because most specimens have been reared from fir.

Hosts and Phenology

Sirex abietinus was reared mainly (83%) from Abies spp. (Pinaceae) (Morris 1967 [as S. cyaneus from Abies lasiocarpa]). Kirk (1975) reared 453 specimens from Abies concolor and Picea engelmannii, but we suspect that most of the specimens reared from firs are S. abietinus and most of the specimens reared from spruce are S. nitidus. Based on 68 reared and confirmed specimens, other hosts are: Abies amabilis (2), A. lasiocarpa (56) (reported by Morris (1967) under the names S. cyaneus and S. juvencus), Picea engelmannii (4), P. glauca (may not have been reared) (1), P. sitchensis (may not have been reared) (1), and Tsuga heterophylla (4). We have only one record from Cupressus macrocarpa (Cupressaceae).

Based on 30 field collected specimens, the earliest and latest capture dates are July 20 and September 15. The main flight period is from late July to mid September with a peak in August.

Range

CANADA: AB, BC, YT. USA: CA, CO, MT, NV, OR, UT, WA, WY. Sirex abietinus, a western North American species, is known from southern Yukon and British Columbia south to California and Colorado (Fig. C4.4). It has been intercepted in England (Saunt 1924). We have seen one male from New Zealand (FRNZ).

Specimens studied and included for range map: 111 females and 44 males from BYUC, CNC, DEBU, EDUM, MTEC, OSAC, PFRC, USFS–GA, and USNM.

Specimens for molecular studies: 5 specimens. See Fig. E2.5e.

CANADA. British Columbia: 2008, CNCS 1029, 601; 2000, SIRCA 053, 612; 1969, SIRCA 064, 583; 2000, SIRCA 069, 553. USA. California: 1999, CBHR 103, 658.