<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 graeca
J.P.E.F.
Stein, 1876
Xyela graeca
J.P.E.F.
Stein, 1876: 57–58
,
♀
,
type
locality:
Greece
, Nomos Ioanina, Konitsa S
6 km
;
Konow 1897: 58
(junior synonym of
julii
);
Benson 1938: 33
, 35 (removed from synonymy).
Pinicola graeca
:
André 1881: 468
(combination with
Pinicola
).
Xyela nigrae
Rasnitsyn, 1965: 519
,
♀
,
type
locality:
Ukraine
,
Transcarpathia
, Tur’i-Remety near Perechin;
Rasnitsyn 1971:
193 (junior synonym of
graeca
).
FIGURE 14.
Emergence phenology of imagines of
Xyela curva
,
X. graeca
and
X. menelaus
under laboratory conditions between 24.3. (= day 1) and 19.4.1999 (= day 25). Rearing data from two almost syntopic samples (Z42A/98, Z42B/98) taken from
Pinus nigra pallasiana
in southern Turkey in 1998.
FIGURE 15.
Records of
Xyela graeca
(553 specimens from 53 collection sites) and natural distribution of the host plant,
Pinus nigra
(solid line, combined from
Meusel et al. 1965
and
Barbéro et al. 1998
).
Description
. Female. Color. Head yellow with black and brown pattern: black stripes along frontal furrows often fading and at most 2 times wider than ocellar diameter, meeting black ocellar and postocellar area, black longitudinal medial spot of frons always present, weak in pale specimens, rarely fusing with frontal stripes, kidneyshaped spots on vertex separate from black postocellar area (
Fig. 51–52
). Antennae brown or pale brown, scape sometimes yellow. Thorax dorsally brown with rich yellow pattern on pronotum, mesonotal lobes and mesoscutellum, tegulae yellow and sometimes brown in middle, mesepisternum largely pale yellow. Abdominal terga brown, lateral parts of terga 7, 8 and 9+10 yellow or pale brown, valvifer 2 completely yellow or pale brown, membrane between valvifer 2 and valvula 3 white, valvula 3 varying from yellow to pale brown (
Fig. 107
). Legs pale brown, posterior coxae pale brown or yellow and more or less infuscate from base. Wing membrane clear, venation and pterostigma pale.
Morphology. Fore wing
2.6–3.9 mm
long, 1.90–2.35(–?2.55) times longer than ovipositor sheath, vein Rs+M 130–280 µm long, 2r-m meeting Rs proximal to furcation of Rs1 and Rs2. Synantennomere 3 510–710 µm long, antennomere 4 130–160 µm long and 4.5–5.5 times longer than wide distally. Article 3 of maxillary palp 410–480 µm long, 1.65–1.85 times longer than scape and wider than synantennomere 3. OOL: POL = 1.60–2.00: 1. Ovipositor sheath (1.35–)
1.60–1.80 mm
long, valvula 3 (?1.60–)1.70–2.00 times longer than valvifer 2 and (?4.5–)4.8–5.8 times longer than wide at base (
Fig. 107
). 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 straight and compressed. Valvula 1 with aulax terminating distally, ventral edge sloping up to tip, with ca 13–15 closely spaced oblique annuli in distal quarter, without serrulae, olistether with 4–5 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 3–5 oblique annuli. Posterior tibia
0.80–1.05 mm
long, claws without subapical tooth.
Male. Color. Similar to female, but often generally paler (see
Fig. 53
for color pattern of head). Hypopygium yellow, often also preapical sterna largely yellow.
Morphology. Fore wing
2.9–3.5 mm
long, Rs+M 160–250 µm long, 2r-m meeting Rs (130–)180–280 µm proximal to furcation of Rs1 and Rs2. Synantennomere 3 510–700 µm long, antennomere 4 140–200 µm long and 5.5–7.0 times longer than wide distally. Article 3 of maxillary palp 340–430 µm long, 1.35–1.55 times longer than scape and wider than synantennomere 3. OOL: POL = (1.40–)1.60–2.00(–2.20): 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 (1.70–)1.80–2.00 times longer than wide on medial lobe, lateral lamella distinct and oblique, proximal lobe of penis valve at proximal end round, 0.20–0.30 times as long as valviceps and 0.70–0.80 times as high as medial lobe, excision on lower edge 0.16–0.22 as deep as width of medial lobe, valviceps on medial lobe 1.35–1.55 times wider than on distal lobe, 2 distal flagella present, tip of longer flagellum reaching (0.90–)0.95–1.05 width of distal lobe (
Fig. 142
). Valviceps with median longitudinal sclerotization present, medial lobe almost symmetrical and broad, with 5–10 cone-like sensilla along upper edge and scattered on lateral surface, upper edge between medial and distal lobe with 6–9 setae. Posterior tibia
0.70–0.85 mm
long, claws without subapical tooth.
Barcodes
. GUID
ABU8786
(
2♀
1♂
)
Type material
.
Xyela graeca
.
Neotype
♂
(here designated): “
Greece
,
Nomos Ioanina
,
Konitsa S
6 km
,
650 m
NN [altitude above sea level],
40°06’N
20°46E
, leg.
Blank
&
Kutzscher
c. [collected]
4.5.1999
em. [emerged]
21.3.2000
[rearing number] Z37/99, larva ex
Pinus nigra
[i.e.,
Pinus nigra pallasiana
]”; “
Xyela graeca
J.P.E.F.
Stein, 1876
det.
S. M. Blank
2000”; [rot:] “Neotypus ♂
Xyela graeca
J.P.E.F.
Stein, 1876
des. S. M. Blank 2001”. Genitalia stored inside small vial and kept on pin of type specimen.
DEI
.
Xyela nigrae
. Holotype
♀
: [
Cyrillic
letters:] “
Karpati
, Tur’i-Remety bliz
Perechina
[= Tur’i-Remety near
Perechin
],
15.V.65
,
A. Rasnitsyn
”; [rot:] “
Holotypus
Xyela
nigrae
♀
A. Rasnitsyn
”.
In
good condition.
ZMUM
.
Paratype:
1♀
,
ZMUM
.
Host
plant
.
Pinus brutia
Ten. (
Schedl 1981
)
,
Ο
Pinus nigra
ssp.
laricio
Poir
,
P. nigra
ssp.
mauretanica
Maire & Peyerimhoff
(
Berland 1937
,
1943
),
●
Pinus nigra
ssp.
nigra
Arn.
(
43♀
21♂
from 6 reared samples),
●
P. nigra
ssp.
pallasiana
Lamb.
(
78♀
28♂
from 9 reared samples),
Ο
P. nigra
ssp.
salzmannii
Dunal
,
P. sylvestris
L. (
2♂
from 1 reared sample).
Biology
. In a series reared from two almost syntopic samples of
Pinus nigra pallasiana
taken in southern
Turkey
X. menelaus
hatched significantly earlier than
X. graeca
(females: n[
graeca
] = 10, n[
menelaus
] = 14, U = 9, α <0.001; males: n[
graeca
] = 5, n[
menelaus
] = 11, U = 7, α <0.05; U-test). The difference was on average 6 days. The few
X. curva
from this sample hatched even ca 18 days earlier than
X. graeca
. This corresponds well with
Pschorn-Walcher & Altenhofer’s (2000)
observation, that Austrian
X. graeca
emerge in April, 1 or 2 weeks later than
X. curva
. In fact,
Pschorn-Walcher & Altenhofer (2000)
had a mixture of
X. graeca
and
X. menelaus
on hand.
For additional phenological data see
Blank (2002)
. Specimens collected in
February
1937
in
Algeria
(
Berland 1937
recording
X. julii
from Tikdja in the Djurjura) were identified as
X. graeca
by
Blank (2002)
but they might belong to a species associated with
Pinus halepensis
.
Geographic distribution
.
Austria
,
Croatia
,
France
,
Greece
,
Hungary
,
Israel
,
Italy
,
Spain
,
Turkey
,
Ukraine
(
Fig. 15
). Additionally reported from
Bulgaria
(
Vasilev 1987
), the Slovakian Republic (
Roller 1999
) and
Cyprus
(Schedl 2002 as
X.
“
cf.
graeca
”). These records are likely to be correct but should be re-examined, because they could relate to
X. graeca
or to
X. menelaus
. The record for
Corsica
by
Liston & Späth (2005)
refers to
X. menelaus
.
Remarks
. Among the pale representatives of the
Xyela julii
group with a comparatively short ovipositor two very similar forms occur in the West Palearctic, which both feed on
Pinus nigra
. Corresponding males have an apparent longitudinal sclerotization of the valviceps and a gradually ascending distal edge of the valviceps. The existence of two separate species is well founded upon the recognition of two different forms of penis valves. These species are here called
X. graeca
and
X. menelaus
, and in accordance with
Benson (1960)
the name
menelaus
is applied to the species with the shorter ovipositor (see below for discussion on nomenclature). The sexes of the two species were associated with the help of two reared series from Lower Austria and a reared series from southern
Turkey
. The first series from Hernstein mainly comprised of females with a comparatively long ovipositor and males with a shallowly excised valviceps bearing a narrowly rounded proximal lobe (=
X. graeca
). The second series from Dürnstein contained mainly females with shorter ovipositor and males with deeper excised valviceps having the proximal side of the proximal lobe truncate (=
X. menelaus
). This association of the sexes corresponds with the emergence phenology of specimens from the reared Turkish series (see above and
Fig. 14
).
Unlike the males the discrimination of females of
X. graeca
and
X. menelaus
is often dubious. The relative length of fore wing: ovipositor sheath and valvifer 2: valvula 3, and the absolute ovipositor sheath length exhibit bimodal distributions. Since a wide overlap is considered, the characters in the key will separate some 80 % of the females.
In the barcoding analysis,
three specimens
of
X. graeca
were grouped in a common cluster with 0.93 % intraspecific variability. This cluster is well separated from the cluster comprising specimens identified as
X. menelaus
(
Fig. 23
). The closest neighbor of
X. graeca
is
X. obscura
at an interspecific distance of 6.13 %.
Xyela graeca
was described from
two females
collected in
Greece
.
Stein (1876)
reported his own collection as their place of deposition. Today the collection of J.P.E.F. Stein is preserved at ZMHB (
Groll 2010
), but no corresponding specimen could be found there. Already
Benson (1938)
reported that H. Bischoff, former curator of the
Hymenoptera
section of ZMHB, was not able to trace the
X. graeca
type material, “as it was never received there with the rest of the collection”. As types of other taxa described by
Stein (1876)
like
Lyda maculipennis
(=
Kelidoptera
m.
; see
Blank et al. 1998
) and
Pachycephus smyrnensis
can still to be located in ZMHB, the
syntypes
of
X. graeca
are deemed to be lost.
Stein’s (1876)
pale
Xyela
species
can be assigned to the
X. julii
group because of its knife-like ovipositor sheath.
Konow (1897)
regarded it as a “schwächliches Exemplar” (feeblish specimen) of
X. julii
.
Enslin (1918)
cast doubt on the correctness of Konow’s opinion referring to Stein’s description of the comparatively short and yellow ovipositor sheath.
Benson (1938)
removed
X. graeca
from synonymy and applied the name to a Mediterranean species, which is distributed northwards to
Austria
. Already
Berland (1943)
considered Stein’s description not to allow the recognition of this species, and the assignment of the name to a particular species to remain uncertain as the type is lost. But he maintained the name for a Mediterranean species.
Benson (1960)
added a very similar species from
Greece
,
X. menelaus
, which was considered to differ from all previously known in the world by its very short ovipositor. He omitted to give a reason, why he believed it to be different from Stein’s
X. graeca
, which was also described due to its short ovipositor. Actually, Stein’s description suits both,
X. graeca
and
X. menelaus
, and both may be common on Greek stands of
Pinus nigra
. Interpreting only the original description it is impossible to decide which of them Stein had on hand, as he did not consider the exact proportion of the ovipositor sheath. The designation of a
neotype
is necessary to promote nomenclatural stability by assigning the name
X. graeca
to a distinct Mediterranean species of the
X. julii
group. Differing from the original type series a male specimen has been chosen as a consequence of the ambiguous identification of females (Art. 75.3.5.,
ICZN 1999
). Like the original types it originates in
Greece
. It was reared from
Pinus nigra pallasiana
.
In a footnote
Berland (1943)
mentioned
X. graeca
collection material from the
MNHN
labeled as “
pinicola
, n. sp.” by Abeille de Perrin. However, the name is not available as “
pinicola
”, because it refers to
Pinicola
which has been assessed as a valid generic name in former times (see
Berland 1947
, who refers to the same specimen citing it as “
Pinicola
,
n. sp.
” written with a capital initial letter).
Study of the
X. nigrae
holotype
confirms the synonymy of this name with
X. graeca
, which has already been proposed by
Rasnitsyn (1971)
. Both
X. nigrae
type specimens were reared from
Pinus nigra
.
Schedl (1981)
reported dark “
X. graeca
” females collected from
P. brutia
near Thripi on the Greek island Crete, and accordingly he concluded
P. brutia
to be an additional host plant of
X. graeca
.
Berland (1937
under the name
X. julii
, 1943
) accounted
P. nigra
var.
mauretanica
as a host of
X. graeca
, but the presence of
X. graeca
in
Morocco
or
Algeria
has not been confirmed. Such material belongs to forms which are similar to
X. altenhoferi
(
Fig. 13
) and these host record should be deleted for
X. graeca
.
Single specimens of
X. graeca
occurred in a reared series of
X. julii
from
P. sylvestris
. The sample was taken from a mixed stand of
P. sylvestris
and
P. nigra
in Lower Austria. In northeastern
Germany
P. sylvestris
was found to shed pollen about two weeks earlier than
P. nigra
, but after a cold spring the phenology of both pines may overlap providing females the opportunity to oviposit on an unusual pine species.