ISSN 1911-2173
Revision of the World species of Xeris Costa (Hymenoptera: Siricidae)
CJAI 28 — September 25, 2015

doi: 10.3752/cjai.2015.28

http://zoobank.org/References/1360ED3A-8330-43BD-B051-2DDBBBD76AA0

Henri Goulet1, Caroline Boudreault1 and Nathen M. Schiff2

17. Xeris xylocola Goulet, n. sp.

Fig. C17.1 (female habitus)

Fig. C17.2 (male habitus)

Type material

Holotype. Female (OLML), in perfect condition , labelled [White] “ LAO, Hua Phan Prov. Ban Salui; Phou Pan-Mt 20˚13’30”N / 103˚59’26”E GPS 1350-1900m, 06.05.2010 Leg. C. Holzschuh + locals”; [Red] “HOLOTYPE  Xeris xylocola ♀ H. Goulet, 2015”.

Paratypes (3 females and 1 male). Same locality as holotype except for collecting date. 28-29.iv.2010 (1F, OLML); 19.v.2011 (2M, OLML); 28.v.2011 (1M, OLML); 15-16.v.2012 (1F, OLML).

Diagnostic combination

Among specimens with a light yellow fore wing cell C and with short setae on the head [malaisei, pallicoxae, spectrum, and xanthoceros], X. xylocola is distinguished in both sexes by the narrow shiny surface medially on the pronotum and the widespread coarse pits on most of the lateral surface of the pronotum, in females by the light reddish-brown spot above and below the anterolateral corner of the pronotum, and the reddish-brown flagellum beyond flagellomere 7–10,  and in males by the well outlined yellowish-white spot extending on both sides of the genal ridge (spot basically comma-like).

Description

FEMALE

Color. Head black except for white spot (rarely missing) on gena dorsal to middle of eye; white spot not clear, or not clearly outlined and ventral edge not extending to genal ridge (Fig. B2.103); scape and pedicel black, flagellomere 1–7 or 1–10 black and following flagellomeres light reddish brown; last maxillary palpomere black (Fig. B2.116). Thorax black except for yellowish-white band on pronotum along margin and below anterolateral corner (Fig. B2.125). Fore wing clear except for lightly tinted band in apical 0.25, and near junction of veins CU and 2 cu-a (as in Fig. B2.67); cell C very light yellow (paler in old specimens) (as in Fig. B2.40); most of area ventral to anal cells yellowish brown; veins black but white at base of stigma on both sides of junction with vein 1r-rs (as in Fig. B2.40). Sheath with apical section black and basal section reddish brown.

Head. Distance between nearest eye edge and lateral ocellus edge about 1.5–1.9 times as long as distance between inner edges of lateral ocelli (as in Fig. B2.20). Setae on frons and clypeus 0.6–0.7 as long as as long as diameter of a lateral ocellus (Fig. B2.103). Eye in lateral view (N = 4) with its maximum height 1.29–1.54 times as long as its maximum length (Fig. B2.103), and maximum height of eye 0.50–0.53 times as long as maximum height of head (from transverse ridge on gena above mandible to top of head) (Fig. B2.103), measurements as in Fig. B2.8). Gena in dorsal view with maximum distance between outer edges a little wider than maximum distance between outer edges of eyes (as in Fig. B2.43) (in frontal view outer edges of eyes not intersecting genae) (Fig. C17.5 and as in Fig. B2.5); in lateral view with distance between outer edge of eye and genal ridge 0.35–0.42 times as long as maximum length of eye (Fig. B2.103, measurements as in Fig. B2.77), with few or no pits ventral to genal ridge, and with very small to moderate size pits (diameter of pit 0.15–0.2 times lateral ocellus diameter) between outer edge of eye and genal ridge (mainly near eye) (Fig. B2.103). Transverse ridge above mandible narrow, sharp and mainly smooth (Fig. B2.103). Vertex scarcely pitted and pits medium in size (diameter of pits 0.2–0.25 times lateral ocellus diameter), pits present from dorsoposterior edge of eye to occiput outside postocellar area, absent on most of postocellar area, pits dense and medium in size along all of clearly outlined and gutter-like median furrow but a little more widespread near lateral ocelli (as in Fig. C17.4).

Thorax. Pronotum in dorsal view along lateral margin with irregular ridges between large teeth (as in Fig. B2.95) and in lateral view with coarse polygonal pits on almost all of surface (Fig. B2.125). Propleuron in lateral view with small polygonal pits over most of surface (as in Fig. C12.7); in ventral view generally with dense medium sized teeth often fused laterally with other teeth, with smooth or shallowly meshed surface in between (as in Fig. B2.22). Transcutal furrow of mesonotum obscured by coarse pits, thus mesoscutum and axilla apparently fused (Fig. C17.3). Metanotum with surface posterior to cenchrus and lateral 0.5 of metascutellum coarsely pitted (pit 0.1–1.5 times as wide as diameter of lateral ocellus) (Fig. B2.105). Fore wing in middle 0.3 of vein 2A diverging considerably (as in Fig. C12.6) away from wing edge, and then less (as in Fig. C12.6) abruptly curved away from wing edge; vein 3A absent, reduced to a stump, or extending along posterior margin of wing (N = 4).

Abdomen. Tergum 8 on central area with deeply pitted sculpticells forming transverse lines of various lengths, and lateral margin in central 0.3 shiny (as in Fig. B2.141, insert). Tergum 9 with meshes of microsculpture on ventral half below longitudinal furrow near center clearly impressed and sculpticells slightly raised as scales, meshes above longitudinal furrow near center well impressed and sculpticells clearly scale-like (as in Fig. B2.92, insert); median basin with base (outlined by two lateral black longitudinal furrows; N = 4) 0.8–1.0 times as wide as its median length, with maximum width of basin 1.6–1.7 times as wide as its median length and basin 0.40–0.46 times as long medially as median length of cornus (measurements as in Fig. A3.2). Cornus constricted in dorsal view, its minimum width (at constriction) about 0.8 times as wide as maximum width subapically (as in Fig. C1.15); with large teeth in apical 0.3 (Fig. B2.110). Sheath. Basal section 0.28–0.29 times as long as apical section (N = 4) (Fig. C17.1); lateral surface of apical section with well-defined ridge (as in Fig. B2.13, insert); length 1.3–1.4 times as long as fore wing length. Ovipositor. Lancet with 29–30 annuli (first 15 annuli hard to see, but still outlined (N = 4); junction of basal and apical sections of sheath aligned between 3rd and 4th annuli; major pits present on last 7 or 8 apical annuli before teeth annuli, and with a very small pit on each of the annuli 2–5 or 2–10), and a small pit on each of the annuli 10–13 (as in Fig. C1.18).

MALE

Color. Head generally with dorsal spot behind eye light reddish brown, clearly outlined, larger in size than spot of females, and extending to both sides of genal ridge (basically coma-like) (Fig. C17.2); clypeus, face, gena near mandible and postocellar furrow light reddish brown (except for dorsal spot, other pale spots may not be consistent based on other species of Xeris studied) (Figs. C17.2, C17.4 and C17.5). Pronotum with lateral band clearly outlined, about 0.3 times as wide as pronotal 0.5, the band remaining wide to posterolateral angle, and generally not extending to lateral edge of pronotum (Fig. B2.132). Coxae, trochanters and femora (except yellowish-white apex) black; protibia in basal 0.5 (Figs. B2.112 and B2.132), mesotibia in basal 0.4 (Figs. B2.132 and C17.2), and metatibia in basal 0.1 (Figs. B2.132 and C17.2) sharply light reddish brown, otherwise tibiae black. Pro- and mesotarsomeres 1, 2 and basal 0.5 of 3 light reddish brown, metatarsomere 1 mainly black (extreme base and apical 0.15 light reddish brown), metatarsomeres 2 brown; most of tarsomeres 3–5 of all legs dark brown or black (as in Fig. C17.2).

Thorax. Metatibia with shallow notch on dorsal edge in basal 0.25 (Fig. C17.2).

Taxonomic notes

AXeris xylocola is part of the X. spectrum lineage as shown by the presence of a pit on each of the most basal annuli. Adults of X. xylocola and X. xanthoceros are closely related based on the narrow shiny surface medially on the pronotum. This character state probably applies to both sexes. However, both sexes probably differ in the pit distribution on the lateral surface of the pronotum and in females in the color pattern of the flagellum.

Origin of specific epithet

The specific name “xylocola” means “living in wood” and is characteristic of larvae of Siricidae.

Range

LAOS: Huaphan.

Abdomen. Tergum 9 with meshes of microsculpture on ventral half below longitudinal furrow near center clearly impressed and sculpticells slightly raised as scales, meshes above longitudinal furrow near center well impressed and sculpticells clearly scale-like (as in Fig. B2.92, insert); median basin with base (outlined by two lateral black longitudinal furrows; N = 6) 0.8–1.2 times as wide as its median length, with maximum width of basin 1.4–2.0 times as wide as its median length and basin 0.36–0.41 times as long medially as median length of cornus (measurements as in Fig. A3.2). Cornus constricted in dorsal view, its minimum width (at constriction) about 0.8 times as wide as maximum width subapically (as in Fig. C1.15); with large teeth in apical 0.3 (as in Fig.B2.110). Sheath. Basal section 0.23–0.31 times as long as apical section (N = 43) (Figs. C12.1 and B2.14); lateral surface of apical section with well-defined ridge (as in Fig. B2.13, insert); length 1.2–1.4 times as long as fore wing length. Ovipositor. Lancet with 27–33 annuli (first 15 annuli hard to see, but still outlined; N = 16); junction of basal and apical sections of sheath aligned between 3rd and 4th annuli; major pits present on last 4–5 apical annuli before teeth annuli, and with very small pit on all or almost all of preceding annuli (Fig. C1.18).

MALE

Color. Head with dorsal spot behind eye usually clearly outlined, larger in size than spot of most females, and extending to both sides of genal ridge (basically coma-like) (Fig. C12.4). Pronotum with lateral band narrower than in females (0.3 as wide as pronotal 0.5), the band becoming narrower posteriorly and not extending to lateral edge of pronotum. Coxae black; trochanter generally (94%) completely reddish brown or mainly brown; femora reddish brown to black (in most specimens reddish brown); tibiae light reddish brown in basal 0.3 and sharply separated from black surfaces, protibia light reddish brown with a narrow to wide longitudinal black band in apical 0.5 along outer 0.2–05 of dorsal surface and often with very narrow longitudinal light reddish-brown inner band, mesotibia light reddishbrown with black transverse band in apical 0.6, and metatibia black except for sharply outlined yellowish-white spot at base (Figs. C12.2 and B2.122); tarsi light reddish brown except for black metatarsomere 1 (except for long reddish-brown spot at apex, apical spot longer than basal spot) (as in Figs. B2.118, B2.120 and C12.2).

Thorax. Metatibia with shallow notch on dorsal edge in basal 0.25 (Figs. B2.118 and C12.2).

Taxonomic notes

The type specimen of Ichneumon spectrum is problematic. Taeger (pers. comm.) pointed out that Linnaeus (1758) clearly refers to more than one specimen. Because the specimen in London agrees with the description (Malaise and Benson, 1934), this could be enough for a lectotype designation. For now I agree with Taeger, and it is best to regard this specimen as a syntype rather than the holotype as proposed by Malaise and Benson (1934).

Xeris spectrum was treated by Maa (1949) as a polytypic species. Except for X. himalayensis, this is still so in the latest catalogs (Taeger and Blank 2008, Taeger et al. 2010). As discussed below, X. spectrum has no subspecies and is restricted to the Palaearctic region. We consider X. spectrum auct. as a complex of two species (see “taxonomic notes” under X. pallicoxae).  Xeris spectrum extends from the Atlantic coast to the Pacific coast of Eurasia in temperate and boreal regions.

Two names have been treated as synonyms of X. spectrum: Sirex emarginatus and S. nanus. Despite the generally accepted synonymy proposed by by Klug (1803) for S. emarginatus and Konow (1898b) for S. nanus, without reference to the descriptions and the holotypes we were able to uphold the accepted synonymy of X. emarginatus after our study of images of the male type. The recognition is based on the size and shape of the genal spot and the color pattern at the apex of metatarsomere 1.

Xeris nanus is more complicated. Smetana and Herman (2001) clearly stated that Müller’s private collection (if it ever existed) was destroyed by the British fleet during the siege of Copenhagen in 1801. So we are left only with his description. The male (recognized from the description) of X. nanus best fits males of X. spectrum because Müller (1776) described its legs as reddish brown except for the black metatibia with white basal transverse band [pedibus ferrugineis: tibiis posticis fuscis annulo albo] and the metatarsi annulated [tibiis tarsisque posticis annularis]. If Müller had a male of X. pallicoxae, a less likely event in Norway where X. spectrum markedly dominates, his description of the leg color would have treated the mesotarsus color in the same manner as the metatarsus color because both are annulated. In males of X. spectrum, the pro- and mesotarsomeres are completely reddish brown and clearly not annulated. Therefore, we treat X. nanus as a junior synonym of X. spectrum.

None of the subspecies proposed by Maa (1949) are retained. There is no evidence of gene flow between any of Maa’s subspecies of X. spectrum. All of them, except X. spectrum townsei Maa, a junior synonym of X. indecisus (Schiff et al. 2012) differ constantly in color pattern and structures. See “Taxonomic notes” under each of the mentioned names for more information on color and structural differences. Xeris malaisei, a species originally from Taiwan, is widespread in northern China, Korea, Japan and extreme southeastern Russia. In the northern part of its range, X. malaisei is sympatric with X. spectrum. Xeris cobosi was not known to Maa (1949) but was included as a subspecies of X. spectrum by Viedma and Suárez (1961) and its status remained as such (Taeger and Blank 2011, Taeger et al. 2010). Xeris cobosi is related to but distinct from X. himalayensis. Xeris spectrum is distinguished from X. pallicoxae in females by coxal color pattern and the distribution of a very small pit on each of the annuli anterior to typical annuli with larger pit before teeth annuli, in males by the color pattern of the mesotarsomere 1 (usually), and in both sexes by the sculpture on the marginal yellowish-white band of the pronotum (the most easily evaluated character state) and the vertical lateral surface of the pronotum, and by the sculpture on the lateral and ventral surfaces of the propleuron. Xeris spectrum is distinguished from X. malaisei in females by the shape of fore wing vein 2A and the flagellum color pattern and in males by coxae and tarsi color. The North American populations considered till recently as X. spectrum spectrum are specifically distinct from X. spectrum and consist of two very similar species, X. caudatus and X. melancholicus (Schiff et. al., 2012). These two American species are distinguished from X. spectrum in females on coxal color pattern, the distribution of annular pits on annuli anterior to the apical annular group of major pits, in males on tibial color pattern at base (best seen on metatibia), and in both sexes on the dark brown base of stigma at junction with vein 1r-rs and the yellowish-brown fore wing cell C, and on pit size and abundance on gena between eye and genal ridge.

Xeris umbra, X. xanthoceros and X. xylocola, though more darkly colored, are related to X. spectrum and X. malaisei because of the presence of an extremely small pit on each of the basal annuli. X. umbra, the darkest species of Xeris, is distinguished from X. spectrum in both sexes by the size of setae on the clypeus and the leg color pattern, in females by the sculpticells centrally on tergum 8 and the teeth size in apical 0.3 of the cornus, in males by the almost completely or completely black legs. X. xanthoceros and X. xylocola are distinguished from X. spectrum in both sexes by the narrow shiny surface medially on the pronotum in dorsal view, and the mainly black pronotum in dorsal view, and in females by the light reddish-brown flagellum in apical 0.5–0.7.

Finally, the user should be aware that the refences based on European specimens could refer to X. spectrum, X. pallicoxae, or both species.

Geographical variation

Adults of X. spectrum show one difference in color pattern between Europe and the far eastern regions of Asia. Near the Pacific coast, the few females studied have completely black coxae. We cannot evaluate this color change as we did not have access to specimens between Europe and the Pacific coast drainage area. The change may be restricted to the Pacific drainage area or it may gradually change across Russia.

Hosts and phenology

We studied 291 specimens (BMNH) of X. spectrum collected by P. J. Spradbery and A. A. Kirk between 1963 and 1970. Each specimen’s label includes the name “Frank Wilson” who did not collect the specimens but supervised the rearing program sponsored by the Australian government. This is only a portion of about 6205 specimens of X. pallicoxae and X. spectrum collected by them.

The results of the emergence period and the host range published (Spradbery and Kirk 1978) is based on a mixture of specimens of X. pallicoxae and X. spectrum. Their emergence period of “X. spectrum” was based on specimens from Turini in southeastern France. We saw about 35% (67 specimens) of their Turini sample. This sample consists of 79% X. pallicoxae and 21% X. spectrum. Most specimens of X. spectrum are from central and northern Europe so we pooled 284 specimens to determine phenology. The emergence cycle started in late May and ended in late July with only one clear emergence peak in late June (C12.8). These results are similar over the years, but there could be a general shift of one week either way. Xeris pallicoxae in contrast shows two emergence peaks during the same period with two clear peaks, one in early June and another in late June, and a very small emergence in late summer.

Xeris spectrum has a moderately wide host range within Pinaceae. Based on 150 specimens (20% of specimens at the BNMH) from Spradbery and Kirk, X. spectrum was reared from Abies alba (fir) and Picea abies (spruce). Amazingly, 90% of specimens were reared from Picea abies. This may reflect a relatively greater abundance of spruces than firs in some of the sites sampled by Spradbery and Kirk rather than a marked preference of X. spectrum for spruce. Spruces are common north of France and very uncommon in the Mediterranean region, based on their known distribution and their samples host data (Spradbery and Kirk 1978).  Spradbery mentioned other hosts, but we are not sure yet if they should be assigned to X. spectrum. Except for intercepted specimens from New Zealand and the United States (acronym given in square brackets), the following published data under X. spectrum almost certainly includes specimens of X. pallicoxae. The hosts are Pinaceae: Abies sp. [FRNZ], A. alba (Enslin 1918, Spradbery et al. 1978), A. borisii-regis (Spradbery et al. 1978), A. cilicia (Spradbery et al. 1978), A. equi-trojan (Spradbery et al. 1978), Larix decidua (Spradbery et al. 1978), Picea sp. [FRNZ], P. abies (Enslin 1918, Spradbery et al. 1978) [FRNZ, USNM], P. orientalis (Spradbery et al. 1978), P. sitchensis (Spradbery et al. 1978), Pinus sp. [FRNZ], P. pinaster (Spradbery et al. 1978), and P. sylvestris (Enslin 1918, Spradbery et al. 1978).

Spradbery and Kirk (1978) listed parasitoids associated with larvae of X. spectrum and almost certainly those of X. pallicoxae. They included Ibalia leucospoides leucospoides (Hochenwarth), I. rufipes drewseni (Borries) (Ibaliidae ) and Megarhyssa emarginatoria (Thunberg), Rhyssa persuasoria (Linnaeus), and R. amoena (Gravenhorst) (Ichneumonidae).

Range

Range

EUROPE: AUSTRIA, BELGIUM, CZECH REPUBLIC, FINLAND, FRANCE, GERMANY, HUNGARY, ITALY, NETHERLANDS, NORWAY, POLAND, ROMANIA, RUSSIA (Transbaikal), SPAIN, SWEDEN, SWITZERLAND, and TURKEY.
Benson (1955) reports a specimen from Israel emerged from pine timber imported from Yugoslavia (Benson, 1955). Eastern Asia: Japan, Russia. Xeris spectrum has a transpalaearctic range from Scandinavia to easternmost Russia and Japan (apparently very rare). In Europe it is known as far south as Spain, Italy, and Hungary. Most specimens seen were north of France and Switzerland. The species no doubt occurs in northern China (Maa 1949) but we have not seen specimens.

Numerous specimens of Xeris spectrum have been intercepted at ports in the United States (7) and New Zealand (14) from the following European countries: Belgium (United States and New Zealand), Germany (United States and New Zealand), Italy (United States), Netherlands (New Zealand), Poland (United States), Russia (Japan), Switzerland (New Zealand), Turkey (United States). The species is not established outside Europe.


Specimens studied: 195 females and 250 males from BMNH, CNC, NMST, SDEI, SDEI – Col. E. Jansen, USNM, and ZMUN.

Specimens for molecular studies: 16 specimens. See Fig. D1.2d. For each specimen the following is recorded: country, year, state/province, specimen code (in italics), and number of base pairs.

EUROPE. Austria: S69, 658. Germany: 1975, S64, 658; 1977, S216, 658; 1977, S272, 658; 1977, S274, 658; 1977, S342, 658; 1978, S355, 658; 1977, S373, 658; 1977, S376, 658; 1977, S464, 658. France: 1978, S220, 658. Italy: 2005, CBHR 41, 658; 1978, S235, 658. Japan: 1977, S375, 658. Netherlands: 2007, CBHR 1090, 658. Russia (eastern): SIR 161.

EUROPE. Austria: S516, 631. Belgium: 1975, S65, 658. France: 1978, S293, 658; 1977, S497, 658. Germany: 1979, S68, 658; 1977, S473, 658; 1978, S179, 658; 1978, S198, 658; 1977, S269, 658; 1978, S296, 658; 1977, S344, 658; 1977, S347, 658; 1978, S394, 658; 1978, S426, 658; 1981, S442, 658; 1977, S474, 658; 1977, S487, 658. Italy: 1971, S76, 658; 1972, S82, 658; 1973, S126, 658; 1977, S264, 658.