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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 noctilio Fabricius

Fig. C14.1, Schiff et al. 2006: 50, 51 (female habitus)
Fig. C14.2, Schiff et al. 2006: 49 (male habitus)
Fig. C14.3 (live female)
Fig. C14.4 (live male)
Fig. C14.5 (live male checking a female)
Fig. C14.6 (live mating pair)
Fig. C14.7 (male moving away)
Fig. C7.7  (map)

Sirex noctilio Fabricius, 1793: 130. Holotype, male, not examined. Type depository unknown (Viitasaari and Midtgaard 1989); but supposedly in the “Sehested” collection, ZMUC; Benson 1943: 36, Burks 1958: 16, Smith 1979: 127. Type locality: “Germania”.
Sirex melanocerus Thomson, 1871: 328. Taeger et al. 2010.
Paururus atlantidis Ghiji, 1909: 163-170. Taeger et al. 2010.


Diagnostic Combination

Among females with a light reddish brown metafemur and black abdomen [abietinus, pale legged form of californicus, cyaneus, nitidus and varipes], those of S. noctilio are recognized by the large median pits on the lancet of the ovipositor (pit 0.5–0.75 times as long as annulus) and the short tarsal pads (tarsal pad of metatarsomere 2 0.2–0.4 times as long as ventral length of tarsomere 2). Among males with a reddish brown metafemur and a mainly black metatibia and metatarsomere 1 [abietinus, cyaneus, nitidus and varipes], those of S. noctilio are recognized by the wide reddish brown base of the metatibia (reddish brown area 2.0–3.0 times as long as minimum width of tibia at base).

Description
FEMALE

Color. Body, antenna and palps black with dark blue metallic reflections. Coxae and apical tarsomeres black (Fig. B2.66); femora (except brown base), tibiae and tarsi light reddish brown (some specimens from the Mediterranean region have black femora, but this color pattern has not been seen in North America). Fore wing basically clear except for brownish yellow spot behind stigma (spot black with dark purple reflections on live specimens).

Head. Gena with pits very fine and 4.0–10.0 pit diameters apart, vertex and postocellar area with pits 2.0–8.0 pit diameters apart (maybe much denser in some specimens) (Fig. B2.61), and each pit diameter about 0.1–0.2 times lateral ocellus diameter.

Thorax. Mesoscutum mostly with round pits in median area (Figs. B2.63 & B2.64), pits commonly with tooth-like process behind, and teeth rarely fused transversally (Fig. B2.64). Metatarsomere 2 in lateral view 2.9–3.5 times as long as high, and its length about 1.1–1.4 times tarsomeres 3 + 4) (Fig. C14.8); tarsal pad 0.3–0.4 times as long as ventral length of tarsomere (Fig. B2.66). Fore wing vein 3A absent.

Abdomen. Median basin of tergum 9 with basal width 0.9–1.1 times as long as median length, maximum width 1.1–1.3 times as long as median length, and median length 0.5–0.7 times as long as cornus length. Cornus in dorsal view short, with edges straight, its median length 1.0–1.2 times as long as maximum width of abdomen at junction of terga 9 and 10. Sheath. Length 0.6–0.75 times fore wing length, basal section 1.05–1.28 times as long as length of apical section. Ovipositor. Lancet with 33–37 annuli (basal annuli clearly outlined); junction of basal and apical section of sheath aligned between 14th and 15th to 16th and 17th annuli, with 29–33 pits beginning with annulus 2; pit of annulus 2 only extending to annulus 1. Pits near middle annuli (Fig. B2.68) or area at base of apical section of sheath 0.55–0.75 times as long as an annulus (pits at base a little smaller: about 0.7 times as high as middle pits), about 0.6–0.75 times as high as lancet height in lateral view, and about 1.4–2.0 times as long as high; annulus 10 length/ovipositor diameter (lance + lancet) not measured. Last 4-5 annuli before teeth annuli as well as first tooth annulus with ridge on ventral edge of pit. Edge of apical 3-5 annuli before teeth annuli extending as ridge to ventral edge of lancet.

MALE

Color. Head, thorax, antenna (flagellomeres 1 and 2 sometimes brown), palps, and coxae black with dark blue metallic reflections. Femora (except brown base), tibiae and tarsi of fore and middle legs light reddish brown; metatibia and metatarsus black (except metatarsomere 4 and at least base of 5 reddish brown); reddish brown spot at base of metatibia 2.0–3.0 times as long as minimum width of tibia at base (Fig. B2.124). Fore wing light yellowish brown. Abdomen black on segments 1–2 and on segment 8 (including sternum 9).

Thorax. Metatibia 3.8–4.2 times as long as maximum width (Fig. B2.124). Metatarsomere 1 in lateral view 2.7–3.8 times as long as maximum height.

Taxonomic Notes

Viitasaari and Midtgaard (1989) mentioned that there were no type specimens of S. noctilio in the Fabricius collection (ZMUC). We were also able to confirm that the type is not in ZMUC (Vilhelmsen, personal communication). However, in the Linnean Collection (LSUK), there are 3 males of S. noctilio. One of the specimens, labelled “S. noctilio Fab.”, was collected by “Cromer Mrs Kett.” four years after Fabricius’ description and matches it perfectly. Though this specimen is not the type, it gives us a good idea that Linnaeus considered his Ichneumon juvencus (images of lectotypes in the Linnean Collection seen by HG) distinct from Sirex noctilio.

The original description is rather informative. First, Fabricius (1793) had a male (number of specimens not indicated) because both in his brief and long descriptions he clearly stated that the abdomen was reddish brown on the middle segments and blue on the basal and apical segments. Second, he wrote that the antennae are black, and the legs other than the hind legs (coxa, tibia and tarsus) are reddish brown. In Germany, only three species of Sirex are known: S. noctilio, S. juvencus and S. torvus. It is not S. juvencus based on antennal and abdominal color patterns. It is not the European S. torvus based on abdominal and mid leg color patterns. So, the present day concept of S. noctilio seems to fit perfectly with Fabricius’ description.

Geographical Variation

Most specimens of S. noctilio have light reddish brown femora and in females clear wings. However, we discovered 20 specimens (USNM, all intercepted at American ports) with black femora and in females dark tinted wings. Pale legged specimens are found all over Europe, but dark legged ones are recorded from southern Europe only. Moreover, it seems that there are no specimens with intermediate color patterns (Figs. C14.9 & C14.10). All structures and color patterns other than the femoral and wing color patterns are the same between the two color forms. Therefore, the dark legged color form is considered as a discrete color form of the common and widespread pale legged S. noctilio. Specimens with dark femora are recorded from the Azores (see Ghigi 1909: 163 under Paururus atlantidis), Portugal, Spain, Italy, and Turkey. The pale form is seen everywhere in Europe. In North and South America only the form with light reddish brown femora is recorded.

Biological Notes

Hoebeke et al. (2005) briefly summarized the biology of S. noctilio. Females attack Pinus spp. in Europe as well as in North America. Development requires one or two years. Adults live one or two weeks and do not feed. Females lay one to three eggs at each oviposition hole. During oviposition, they introduce a toxic mucus with the spores (oidia) of Amylostereum areolatum (Fries: Fries). Larvae can develop only on this fungus. A female can use the same oviposition hole to drill one or more lateral holes to oviposit (Viitasaari 1984). Females may lay 75–400 eggs. The largest batch of eggs comes from the largest females (Chrystal 1928, Rawlings 1953, Coutts 1965). Adults dig themselves out and leave exit holes from 3–7 mm in diameter (dependant on adults size (9–35 mm). Adults are able to fly several kilometers.

Hosts and Phenology

Based on over 100 reared and confirmed specimens in North America, the hosts of S. noctilio are various Pinus spp. (Pinaceae). We have seen specimens reared from P. resinosa, P. sylvestris, and P. strobus. In addition S. noctilio has been recorded from P. caribaea, P. contorta, P. echinata, P. elliottii, P. kesiya, P. nigra, P. palustris, P. patula, P. pinaster, P. pinea, P. radiata, and P. taeda. In Europe, S. noctilio has been reared from Pseudotsuga menziesii and in New Zealand and Australia on Pinus radiata. The wider host range recorded from Europe may be due to accumulated information from misidentified specimens of other species of Sirex.

Based on 66 field-collected specimens, the main flight period is from early July to first half of October with a peak in the second half of July and the first half of August.

Range

ARGENTINA: Rio Negro, Entre Rios, Corrientes, Misiones, Buenos Aires, Cordoba Jujuy (Allard 2008a). BRAZIL: Paraná, General Carniero. CANADA: MB, ON, QC. CHILE: IX and X regions (Allard 2008b), Patagonia, Dina Huapi (Villacide 2010). USA: MI, NY, OH, PA, VT. URUGUAY. Though the range of S. noctilio is originally from Europe to Siberia, it became accidentally established into Australia (Gilbert and Miller 1952), New Zealand (Gourlay 1951, Rawlings 1955), and South Africa (Taylor 1962, Tribe 1995, Tribe 1997). The species was also introduced into South America (Haugen and Hoebeke 2005) and recently into the Great Lake region of North America (Fig. C7.7). The earliest record in North America is a specimen (BMNH) from the Albany River, Ontario, Canada, which ends at James Bay (Benson 1943). It was collected in the early 1800s. Despite some collecting in northern Ontario and intensive collecting in northern Manitoba, no other specimen has been found. It may be an intercepted specimen if it was originally collected near Fort Albany. Sirex noctilio became established around Lake Ontario (Ontario and New York) in early 2000 (Hoebeke et al. 2005).

Specimens studied and included for distribution map: 313 females and 114 males from CFIA, CNC, CUIC, FRNZ, GLFC, ICCM, NZAC, PANZ, USFS–GA, and USNM.

Specimens for molecular studies: 127 specimens. See Fig. E2.5c.

ARGENTINA: 2005, CBHR 48, 658; 2005, CBHR 49, 658; 2005, CBHR 52, 658; 2005, CBHR 53, 658.

AUSTRALIA: year unknown, CBHR 15, 658; year unknown, CBHR 16, 658; year unknown, CBHR 17, 658; year unknown, CBHR 39, 658.

CANADA. Ontario: year unknown, CBHR 286, 658; 2007, SIRCA 18, 615; 2007, SIRCA 19, 616; 2007, SIRCA 20, 620; 2007, SIRCA 21, 628; 2007, SIRCA 22, 606; 2007, SIRCA 45, 612; 2007, SIRCA 46, 658; 2007, SIRCA 47, 620.

SOUTH AFRICA: 2007, CBHR 1085, 658.

USA. New York: 2005, CBHR 20, 658; 2005, CBHR 21, 658; 2005, CBHR 22, 658; 2005, CBHR 23, 658; 2005, CBHR 24, 658; 2005, CBHR 25, 658; 2005, CBHR 26, 658; 2005, CBHR 27, 658; 2007, CBHR 805, 658; 2007, CBHR 807, 658; 2007, CBHR 810, 658; 2007, CBHR 811, 658; 2007, CBHR 814, 658; 2007, CBHR 815, 658; 2007, CBHR 817, 658; 2007, CBHR 819, 658; 2007, CBHR 824, 658; 2007, CBHR 826, 658; 2007, CBHR 827, 658; 2007, CBHR 828, 595; 2007, CBHR 829, 658; 2007, CBHR 834, 658; 2007, CBHR 836, 658; 2007, CBHR 837, 611; 2007, CBHR 1011, 658; 2007, CBHR 1012, 658; 2007, CBHR 1013, 658; 2007, CBHR 1014, 658; 2007, CBHR 1015, 658; 2007, CBHR 1016, 658; 2007, CBHR 1017, 658; 2007, CBHR 1018, 658; 2007, CBHR 1019, 658; 2007, CBHR 1020, 658; 2007, CBHR 1021, 658; 2007, CBHR 1103, 658; 2007, CBHR 1104, 658; 2007, CBHR 1105, 658; 2007, CBHR 1106, 658; 2007, CBHR 1107, 658; 2007, CBHR 1108, 658; 2007, CBHR 1109, 658; 2007, CBHR 1110, 658; 2007, CBHR 1111, 658; 2007, CBHR 1112, 658; 2007, CBHR 1113, 658; 2007, CBHR 1114, 658; 2007, CBHR 1115, 658; 2007, CBHR 1116, 658; 2007, CBHR 1117, 658; 2007, CBHR 1118, 658; 2007, CBHR 1119, 658; 2007, CBHR 1124, 658; 2007, CBHR 1125, 658; 2007, CBHR 1126, 658; 2007, CBHR 1127, 658; 2007, CBHR 1128, 658; 2007, CBHR 1129, 658; 2007, CBHR 1130, 658; 2007, CBHR 1131, 658; 2007, CBHR 1132, 658; 2007, CBHR 1133, 658; 2007, CBHR 1134, 658; 2007, CBHR 1135, 658; 2007, CBHR 1136, 658; 2007, CBHR 1137, 658; 2007, CBHR 1138, 658; 2007, CBHR 1139, 658; 2007, CBHR 1140, 658; 2007, CBHR 1141, 658; 2007, CBHR 1142, 658; 2007, CBHR 1143, 658; 2007, CBHR 1144, 658; 2007, CBHR 1145, 658; 2007, CBHR 1146, 658; 2007, CBHR 1147, 658; 2007, CBHR 1148, 658; 2007, CBHR 1149, 658; 2007, CBHR 1150, 658; 2007, CBHR 1151, 658; 2007, CBHR 1152, 658; 2007, CBHR 1153, 658; 2007, CBHR 1154, 658; 2007, CBHR 1155, 658; 2007, CBHR 1156, 658; 2007, CBHR 1158, 658; 2007, CBHR 1159, 658; 2007, CBHR 1160, 658; 2007, CBHR 1161, 658; 2007, CBHR 1162, 658; 2007, CBHR 1163, 658; 2007, CBHR 1164, 658; 2007, CBHR 1165, 658; 2007, CBHR 1166, 658; 2007, CBHR 1167, 658; 2007, CBHR 1168, 658; 2007, CBHR 1169, 658; 2007, CBHR 1170, 658; 2007, CBHR 1171, 658; 2007, CBHR 1172, 658; 2007, CBHR 1173, 658; 2007, CBHR 1174, 658; 2007, CBHR 1175, 658; 2007, CBHR 1176, 658; 2007, CBHR 1177, 658. Pennsylvania: 2007, CBHR 992, 658; 2007, CBHR 993, 658; 2007, CBHR 994, 658; 2007, CBHR 995, 658.