<strong> The Eurasian species of <em> Xyela </ em> (Hymenoptera, Xyelidae): taxonomy, host plants and distribution </ strong>
Author
Blank, Stephan M.
stephan.blank@senckenberg.de.
Author
Shinohara, Akihiko
shinohar@kahaku.go.jp.
Author
Altenhofer, Ewald
stephan.blank@senckenberg.de.
text
Zootaxa
2013
2013-03-18
3629
1
1
106
http://dx.doi.org/10.11646/zootaxa.3629.1.1
journal article
53391
10.11646/zootaxa.3629.1.1
9bac424f-e31f-4780-a976-f4fe3ba62156
1175-5326
5261330
FF47F026-9CB6-4390-B900-130A3DF2B33B
Xyela julii
(
Brébisson, 1818
)
Pinicola julii
Brébisson
[reported by Blainville], 1818: 117,
♂
,
type
locality:
Austria
,
Lower Austria
,
Hörweix
near
Etzen
.
Xyela julii
:
Konow 1897: 57
(combination with
Xyela
)
Xyela pusilla
Dalman, 1819: 124
, figs 1–11,
♂
,
type
locality:
Sweden
, Uplandia and Vestrogothia [=
Uppsala län
,
Västmanlands län
, Skaraborgs län or Älvborgs län];
Lepeletier & Serville 1828: 792
(junior synonym of
julii
).
Xyela henschii
Mocsáry, 1912: 131
,
♂
,
type
locality:
Croatia
, Krapina;
Blank 2002: 222
(junior synonym of
julii
).
Xyela henschi
:
Enslin 1918: 682
(misspelling).
Description
. Female. Color. Head yellow with black and brown pattern: at least two black stripes along supraantennal furrows meeting black ocellar and postocellar area and longitudinal spot in middle of frons present, often dark pattern fusing to large dark sport of the frons; kidney-shaped spot on vertex often not confluent with black postocellar area (
Fig. 60
). Antennae brown. Mesoscutum black with yellow pattern on medial half of lateral lobes, mesoscutellum with yellow spot. Mesepisternum pale except for brown dorsal, posterior and ventral margins. Abdominal terga brown, lateral parts of preapical terga, partly distal sternum, valvifer 2 and valvula 3 pale brown, membranous base of valvula 3 whitish, tip of valvula 3 darkened (
Fig. 109
). Legs mainly pale brown, femora unicolorous pale, posterior coxae mainly dark brown. Wing membrane, venation and pterostigma pale brown.
Morphology. Fore wing
2.8–4.3 mm
long, (1.60–)1.70–1.90 times longer than ovipositor sheath, vein Rs+M 180–280 µm long, 2r-m meeting Rs proximal to furcation of Rs1 and Rs2. Synantennomere 3 560–690 µm long, antennomere 4 130–160 µm long and 3.5–5.5 times longer than wide distally. Article 3 of maxillary palp 390–490 µm long, 1.45–1.65 times longer than scape and wider than synantennomere 3. OOL: POL = (1.30–)1.40–1.65(–2.00): 1. Ovipositor sheath (1.60–)
1.90–2.40 mm
long, valvula 3 2.00–2.35 times longer than valvifer 2 and 6.5–8.0 times longer than wide at base (
Fig. 109
). Valvula 3 of ovipositor compressed, pale membranous area about as long as basal width of valvula 3, dorsal edge of valvula 3 sloping down to round tip, distally with sensilla field exposed and directed caudally, bearing 3 setae. Ovipositor almost straight and compressed. Valvula 1 with aulax terminating distally, ventral edge sloping up to tip, with ca 15–16 oblique closely spaced annuli in distal quarter, without serrulae, olistether with 6 setae. Left and right valvulae 2 fused along dorsal edge in basal half. Valvula 2 with smooth dorsal margin, tapering in distal half, pale and evenly sclerotized, in distal 0.4 with single scattered sensilla campaniformia, in distal 0.1 with 5–6 oblique annuli. Posterior tibia
0.75–0.95 mm
long, claws without subapical tooth.
Male. Color. Variability of coloration similar to female but usually paler (see
Fig. 61
for color pattern of head), hypopygium brown to dark brown.
Morphology. Fore wing
3.1–3.7 mm
long, Rs+M 75–250 µm long, 2r-m meeting Rs proximal to furcation of Rs1 and Rs2. Synantennomere 3 540–650 µm long, antennomere 4 140–170 µm long and 4.0–6.0 times longer than wide distally. Article 3 of maxillary palp 350–410 µm long, 1.35–1.55 times longer than scape and wider than synantennomere 3. OOL: POL = (1.30–)1.40–1.75: 1. Longitudinal apodeme of basiparamere curved, basal portion in lateral position, harpe about as long as wide in lateral view. Lower ergot on valvular stalk absent. Valviceps 1.50–1.60(–1.70) times longer than wide on medial lobe, with distinct oblique lateral lamella, proximal lobe of penis valve 0.23–0.29 times as long as valviceps and 0.70–0.75 times as high as medial lobe, excision on lower edge 0.22–0.27 as deep as width of medial lobe, valviceps on medial lobe (1.10–)1.20–1.25 times wider than on distal lobe, 2 distal flagella present, tip of longer flagellum reaching 0.65–0.75 width of distal lobe (
Fig. 144
). Valviceps with median longitudinal sclerotization present, medial lobe almost symmetric and broad, with 4–8 cone-like sensilla along upper edge and scattered on lateral surface, upper edge between medial and distal lobe with 8–12 setae. Posterior tibia
0.60–0.85 mm
long, claws without subapical tooth.
Barcodes
. GUID
ABY6138
,
AAJ9260
(
5♀
,
2 larvae
)
Type material.
Pinicola julii
.
Neotype
♀
(here designated): “A [=
Austria
]: Niederösterr. [=
Niederösterreich
,
Lower Austria
]:
Hörweix
(
Etzen
),
31.5.1996
Pinus sylvestris
, em.
18.4.1998
leg.
Ewald Altenhofer
”; “
Xyela julii
(
Brébisson, 1818
)
det.
S. M. Blank
2000”; [red:] “Neotypus ♀
Pinicola julii
Brébisson, 1818
des.
S. M. Blank
2001”.
DEI
.
Xyela pusilla
.
Unknown number of
♀
and
♂
syntypes from “Uplandia” (= historical province
Uppland
; = modern
Uppsala län
or
Västmanlands län
) and “Vestrogothia” (= historical province
Västergötland
; = modern
Skaraborgs
län or
Älvborgs
län).
Type
material lost
.
Xyela henschii
.
Lectotype
♀
(designated by
Blank 2002
): “Dr. Hensch Krapina Cro.”; “
Xyela henschii
Mocs.
typ. det. Mocsáry”; [label with red margin:] “
Lectotypus
♀
Xyela Henschii
Mocsáry, 1912
des. Zombori, 1976”; [label with red margin:] “
Paralectotypus
♂
Xyela Henschii
Mocsáry, 1912
des. Zombori, 1976”; “
Xyela julii
(
Brébisson, 1818
)
♀
♂
det. S. M. Blank 1999”.
Lectotype
missing both valvulae 3, otherwise in good condition.
HNHM
.
Paralectotype
:
1♂
on same mount as
lectotype
, genitalia glued to small slide,
HNHM
.
Host
plant
.
Pinus cembra
L. (
Schedl 1978
),
P. nigra
ssp.
nigra
Arn.
(
1♂
reared, A.P. Rasnitsyn personal communication),
P.
x
rotundata
Link
(
2♀
4♂
from 1 reared sample),
●
Pinus sylvestris
L. (
105♀
54♂
from 9 reared samples; =
Ο
P. hamata
D.Sosn.
from Caucasus),
P. uncinata
Ramond (
Pschorn-Walcher & Altenhofer 2000
)
.
Biology
. In the lowlands and the mountainous regions of Central, West and
East Europe
, and in the high mountains of
Greece
(
1,600–1,800 m
altitude) imagines are active between mid-April and end May. In northern
Finland
and
Sweden
, they occur almost up to the
North Cape
from the end of
May
to the beginning of
July
(Tab. 5).
For
additional data see
Blank (2002)
.
Geographic distribution
.
Austria
,
Belgium
,
Bulgaria
,
Croatia
,
Czech Republic
,
Denmark
,
Finland
,
France
, Georgia (Abkhaszkaya Respublika),
Germany
,
Great Britain Greece
,
Ireland
,
Italy
,
Mongolia
,
Netherlands
,
Norway
,
Poland
,
Russia
(Irkutskaya Oblast, Moskovskaya Oblast, Murmanskaya Oblast, Respublica Gorno-Altay, Ryazanskaya Oblast,
Sankt Peterburg Oblast
), Slovakian Republic,
Spain
,
Sweden
,
Switzerland
,
Turkey
,
Ukraine
(
Fig. 17
). Additionally reported from
Estonia
(
Viitasaari et al. 1998
),
Latvia
(
Tsinovskiy 1953
),
Luxembourg
(
Chevin & Schneider 1988
).
Zombori (1974)
listed it for the Carpathian Basin but there is no material of
X. julii
in HNHM. Records of
X. julii
by
Zirngiebl (1937)
and
Benson (1938)
refer to a form similar to
X. altenhoferi
for North Africa and to
X. variegata
and
X. tecta
for
Japan
. The USNM holds a single female
X. julii
which was intercepted at a
United States
port among cargo on an aircraft from the Rhein-Main Airport in Frankfurt.
Remarks
.
Xyela julii
is similar to the West Palearctic
X. heldreichii
,
X. obscura
and
X. uncinatae
and the East Palearctic
X. pumilae
in the shape of the valviceps with upper edge of proximal lobe almost parallel to the longitudinal axis, medial lobe symmetric, and longitudinal sclerotization apparent. Females of
X. heldreichii
,
X. obscura
and
X. uncinatae
have the head (at least predominantly) dark, whereas in the darkest
X. julii
females the face remains yellow at least along the eyes.
Xyela pumilae
differs in the infuscate wings and the different proportion of the ovipositor sheath. Males and females have been associated by study of extensive series reared from
Pinus sylvestris
.
Imagines of
X. julii
and
X. obscura
cannot be distinguished in the barcoding analysis (
Fig. 23
). Accordingly, it is not possible to identify genetically their larvae extracted from
Pinus mugo
and
P. sylvestris
, but these fall within the same cluster as the imagines of the two species. Specimens of both
X. julii
and
X. obscura
are associated with two subclusters bearing the GUIDs ABY6138 and AAJ9260, but these subclusters remain unreproducible applying morphological approach. The intraspecific variability of
X. julii
is 2.34 % and of
X. obscura
2.66 %. The nearest neighbor,
X. graeca
, is placed at a distance of 6.13%.
Both along altitudinal and geographical gradients the morphology of
X. julii
is rather stable. Usually material from the South is paler than that from the North. Females from Scandinavia often have the face predominantly black leaving only a narrow yellow line along the eye margin, whereas females from
Spain
, Irkutsk and
Mongolia
often have only dark brown to black stripes along the frontal furrows and the medial spot and the kidney-shaped spots more or less disconnected from the other dark pattern of the face.
Xyela julii
is by far the most frequently cited xyelid in faunistic literature (see catalogue of
Smith 1978
). Its comparatively easy availability in the lowlands of Central and North Europe made it the favorite representative of the
Xyelinae
for comparative morphological studies and phylogenetic analysis of the lower
Hymenoptera
(e.g.,
Vilhelmsen 2001
, Sharkey et al. 2012). Astonishingly the original description of
Pinicola julii
has not been reexamined seriously in comparison with the taxa which have been accepted as valid in the course of the past 70 years.
The
Bulletin des Sciences par la Société Philomatique de Paris
, which includes the original description of
P. julii
, is a rare journal, and it was possibly unavailable to most authors.
Konow (1897)
distinguished two European species, the strikingly different
X. julii
and
X. longula
.
Enslin (1918)
followed his opinion, although he expressed some doubt on the status of
X. alpigena
,
X. graeca
and
X. henschi
as synonyms with
X. julii
. Benson was the first who recognized
X. alpigena
,
X. graeca
and
X. julii
for certain among the European species. He added
X. curva
and published a key for the females (
Benson 1938
). Later he separated the dark subalpine form
X. obscura
from
X. julii
, and he described
X. menelaus
(
Benson 1960
)
. Benson’s understanding of
X. julii
has generally been accepted by later authors (e.g.,
Rasnitsyn 1965
,
Schedl 1978
, Zhelochovtsev & Zinovjev 1988,
Blank 2002
), although he never gave a reason for his decision relating the name
Pinicola julii
as described by Brébisson to a particular
Xyela
species.
If the characters given in Brébisson’s original description are considered alone, the identity of
P. julii
is doubtful. Among others the description characterizes the conspicuous antennae, the long article 3 of the maxillary palp (apparently the tiny article 1 was overlooked and article 3 therefore counted as the article 2), the presence of vein Rs+M (“trois cellules sous-marginales, la première reçoit la première nervure récurrente”), and for the female the long, compressed and darkened oviposition apparatus (“une longe et forte tarrière” and “la tarière est grise”). This encompasses the current understanding of both
X. curva
and
X. julii
. Valvula 3 of the ovipositor sheath is black to infuscate in
X. curva
and more or less infuscate in the preapical portion in
X. julii
. Other known European species can be excluded either by coloration, shape of ovipositor sheath, and / or known altitudinal and geographical distribution excluding the collection locality in northeastern
France
.
Brébisson described
P. julii
from Tour (near Falaise,
Normandy
,
France
). Neither
Pinus sylvestris
nor
P. nigra
are autochthonous to
Normandy
(
Mirov 1967
,
Willis et al. 1998
), although we studied
X. julii
from several places in the lowlands of northern
France
.
Xyela curva
may be expected there on cultivated
P. nigra
. Brébisson collected
Pinicola julii
from resin trees (“arbres resineux”) and conifers in the first days of May, and he found it during a period of 15–20 days. This late phenology better fits a lowland population of
X. curva
than of
X. julii
.
The original description of
P. julii
was published under the name of the co-editor of the journal, H. de Blainville (signed by “Bv.”; see editorial board of the journal), but its title refers to “M. [= Monsieur] Brébisson”, who is the responsible person for nomenclatural matter (Art. 52.1
ICZN 1999
). The work is generally assigned to the coleopterist Jean Baptiste Gilles de Brébisson (1760–1832) and not to his son Louis Alphonse de Brébisson (1798–1872), who became famous for his botanical work (
Constantin 1992
). The collection of Brébisson was bought by A. Fauvel, given to Mrs B. Rancin and should have been forwarded to the ISNB later (
Dalibert 1927
,
Constantin 1992
,
Groll 2010
). However, no relevant material could be located at the ISNB according to J.-L. Boevé (personal communication) and during our own study of the complete xyelids housed there. Accordingly the
syntypes
must be regarded as lost.
A
neotype
is necessary to ensure the unambiguous current and future use of the name
Pinicola julii
, because of the absence of original type material and due to conflicting evidence for the proper placement of
P. julii
from the data given in the original description. The
neotype
is selected for that
Xyela
species
, which 1, infests
Pinus sylvestris
; 2, which is the most abundant Central and North European
Xyela
species
, and which has the widest distribution range among
Xyela
species
; and 3, which might be the most frequently cited name for a xyelid species still today (see references in
Smith 1978
). A specimen reared from
Pinus sylvestris
is hereby designated. The
neotype
agrees with the description above, which is covered by Brébisson’s characterization. It originates from the western part of the vast distribution range of
X. julii
as did the original
syntypes
.
Also the
types
of
X. pusilla
must be regarded as lost, because we could not locate concerning material in the NHRS, which includes J.W. Dalman’s collection. The original description, which was accompanied by excellent illustrations, leaves no doubt that
X. pusilla
agrees with
X. julii
. Only
X. julii
and
X. longula
are known from Scandinavia, and within this geographical context the long article 3 of the maxillary palp, the comparatively short ovipositor, and the well developed vein Rs+M on the fore wing (see
Dalman’s [1819]
figs 1a, 2a and 4) unequivocally indicate
X. julii
. Therefore, the current synonymy, first proposed by
Lepeletier & Serville (1828)
, is considered correct.
Pinus sylvestris
is well known to be the host plant of
X. julii
(e.g.,
Rasnitsyn 1965
). The
types
of
X. pusilla
were collected in a
P. sylvestris
wood (
Dalman 1819
).
Rudow (1912)
supposed that he had reared
X. julii
from enlarged shoots of
P. sylvestris
with swollen buds, but obviously his sample contained not only buds infested by the moth
Rhyacionia buoliana
(Denis & Schiffermüller, 1775) (Tortricidae)
but also staminate cones with
Xyela
larvae. Over 140 subspecies, varieties or forms of
P. sylvestris
have been described, but besides the
type
var.
sylvestris
only
var.
hamata
C. Steven
(Balkan peninsula, N
Turkey
, SW Transcaucasia) and
var.
mongolica
Litvinov
(
Mongolia
, NW
China
, S Siberia) are now normally accepted (
Earle 2011
). All these forms are relevant as larval host plants. A female from Georgia was caught on “
P. hamata
” according to its labeling. Records from the Baikal region are inside the range of
var.
mongolica
.
Pinus sylvestris
exhibits the largest distribution area among pines, reaching from
Scotland
almost up to the Pacific Coast in Siberia, from
Norway
to
Spain
and from Arctic Siberia to
Mongolia
.
Xyela julii
apparently follows up to the limits of its host plant’s distribution range. In northern Europe, it was collected in vast number almost up to the North Cape. It is abundant in
Scotland
, where a
P. sylvestris
population became isolated some 4,400 years ago (
Willis et al. 1998
), and later spread from there over
England
apparently along with cultivated trees. The most southern West Palearctic records of
X. julii
are from
Spain
(El Ventorillo) and northern
Greece
(Mt. Kajmakčalan and Mt. Vrondou), where it was found between
1,480
–1,680
m
altitude, and from Georgia (Caucasus National Park). In southern Siberia it occurs in the Altai Mountains (reported as
X. obscura
by
Rasnitsyn 1965
), where
P. sylvestris
grows between
350–700 m
altitude (
Mirov 1967
), and it was collected several times by Verzhutskij in the environs of Irkutsk (see also
Verzhutskij 1966
). The most southeastern record is from
Mongolia
(Hentiyn Nuruu, Bogdo ul).
The exceptional occurrence of
X. julii
on
P. nigra
might possibly have been caused by coinciding host plant phenologies similar to the occurrence of
X. graeca
on
P. sylvestris
.
Pschorn-Walcher & Altenhofer (2000)
reared
X. julii
from
P.
x
rotundata
, but they erroneously quoted
P. uncinata
for “Moor-Spirke” (see
X. uncinatae
for nomenclature of the pines). Pine and reared material have here been checked. Today this pine is mostly considered a variety or subspecies of
P. sylvestris
, which mainly differs in resin chemistry (
Mirov 1967
,
Earle 2011
). Development on
P. cembra
as assumed by
Schedl (1978)
cannot be confirmed. This relationship is very unlikely due to restriction of
P. cembra
to the subalpine zone of the central Alps, where
X. julii
is absent.