Eupelmus vesicularis

Fusu, Lucian, 2017, An integrative taxonomic study of European Eupelmus (Macroneura) (Hymenoptera: Chalcidoidea: Eupelmidae), with a molecular and cytogenetic analysis of Eupelmus (Macroneura) vesicularis: several species hiding under one name for 240 years, Zoological Journal of the Linnean Society 181 (3), pp. 519-603 : 566-569

Eupelmus vesicularis light form – Fusu, 2010: 1114.

Description: Female. Length = 1.0– 3.4 mm. Colour variable but always somewhat tricoloured, with a metallic green head, largely reddish-brown or brownish-yellow mesosoma and brown metasoma ( Fig. 43 ); small specimens sometimes almost uniformly pale yellowish with brownish head. Head usually metallic bright bluish-green to dark green with brown clypeus and with dull bronze reflections mostly along internal eye orbit, parascrobal area and interantennal prominence; frons more or less distinctly tricoloured with green luster along inner orbits (except immediately near them where narrowly coppery) and mesally bronze to dark coppery below level of anterior ocellus; sometimes in large specimens extensively bronze and coppery-red and green only along occipital margin and partly on scrobes. Antenna as described for E. balcanicus . Mesosoma lighter than head; pronotum, prepectus, acropleuron, and mesopectus brownish-yellow to reddish-brown with at most a very faint metallic luster; prosternum and metapleuron brown with green to coppery metallic luster; mesoscutal plate moderately uniformly setose except narrowly asetose posteriorly, brownish on outer sides with reduced metallic luster, the rest bronze-green to coppery and concave part bluish-green medially, except usually narrowly violet near hind margin, or rarely with a very narrow purple median stripe bordered by bluish-green ( Fig. 64 ); in some small specimen mesoscutal plate with reduced, nearly uniform greenish luster; axillae and scutellum anteriorly yellow to reddish-brown, conspicuously contrasting with the rest of scutellum that dorsally is dark brown with dull green luster; scutellar-axillar complex with brownish hair-like setae except setae lighter and slightly lanceolate toward frenal line ( Fig. 64 ). Legs with a pattern of light areas as described for E. balcanicus except general colour reddish-brown; in some smaller specimens legs pale-brown with extensive pale-yellow regions. Metasoma with short and sparse yellowish-brown non-reflective hair-like setae, on Gt2–Gt4 distance between sockets of two adjacent setae about equal to or greater than seta length ( Figs 98, 100 ), setae especially sparse on sides; Gt1 dorsally with single row of 5–15 inconspicuous setae arranged into one distinct row and sometimes with at most 6 setae offset to form an indistinct second row ( Fig. 98 ); with brown to dark brown and at least slightly darker than mesosoma except Gt1 completely translucent, appearing uniformly brownish-yellow to whitish, at most with a pair of darker subbasal spots with indiscernible metallic hue ( Fig. 72 ); in some small specimens metasoma brownish-yellow and concolorous with the mesosoma. Ovipositor sheaths brownish in about apical third with the brown colour variably extending sometimes along ventral margin of sheath, brownish-black at extreme base, and with a yellowish pale band in basal half ( Fig. 43 ), so that in most specimens distinctly banded.

Head in lateral view hemispherical, in dorsal view 1.8–2.1 as broad as long, in frontal view 1.1–1.2× as broad as high. Frontovertex coriaceous-imbricate to reticulate. Pedicel plus flagellum 1.1–1.4× head width. Pronotal ridge with erect setae shorter than pronotal collar. Mesoscutal plate with flat, V-shaped anterior region differentiated by minute reticulate sculpture and posteromedial region finely coriaceous mesally and shallowly concave. Scutellum and axillae weakly convex ( Fig. 64 ). Acropleuron imbricate to slightly reticulate, with microsculptured region medially. Fore wing base extended to near petiole; basal cell densely setose dorsally; apical part normally abruptly bent upward, comparatively short, 1.35–1.7× as long as basal part, with marginal and postmarginal veins extended along straight leading margin and without a trace of a stigmal vein, posterior and leading margins obliquely angled to rounded apex ( Figs 118–120 ). Due to allometry ( Fig. 17 ), in rare very small specimens (only two specimens of 1 mm in length seen), the wing apical part is only 1.1× longer than the basal part and wing apex pointed ( Fig. 121 ). Hind wing concealed beneath fore wing and apically reflexed. Middle leg with row of 3–7 mesotibial apical pegs; mesotarsus with asymmetrical peg pattern on basitarsus, anterior margin with 5–11 pegs in single row ( Fig. 81 ) or sometimes differentiated into two medially slightly overlapping rows ( Fig. 80 ) and posterior margin with three to six pegs (frequently four) within basal half and with ( Fig. 81 ) or without ( Fig. 80 ) one peg apically, second tarsomere with one to three pegs on anterior margin and one peg on posterior margin, and third and fourth tarsomeres with one apical peg on either side. The size correlated reduction of peg number is mostly on anterior margin of the tarsus and even in very small specimens posterior margin of basitarsus with at list three pegs within basal half. Metasoma ovoidal and comparatively narrow, 1.9–2.7× as long as wide, Gt5 alutaceous-granular. Syntergum and anal plate forming truncate to somewhat obliquely inclined surface above ovipositor sheaths and gaster extending to about apex of second valvifer. Ovipositor sheaths 0.4–0.55× as long as metatibia, 0.3× as long as metasoma, and 0.9–1.1 × as long as head.

Male. Thelytokous species.

Comparative diagnosis: Small females of E. messene (about 1 mm in length) are almost entirely yellowish, with a very faint green luster on the head, and thus could be mistaken for E. rameli (see also under this species). The fore wing rudiment in such females has a very short apical part that is also pointed apically, looking very much like that of E. rameli , but the costal cell is much narrower than the basal cell although this is difficult to quantify because the basal cell is convex (cf. Figs 116 with 121).

Some large females of E. messene are darker and can be confused with E. barai and especially E. vesicularis . From E. barai , they are most easily distinguished by their shorter fore wing rudiment and colour, at least parts of the thorax being yellowish-brown, and the metallic luster on the mesoscutum being mostly green without a large violet spot. Females of E. messene usually also have the ovipositor sheaths distinctly banded, with a median pale band, while in E. barai , E. balcanicus , and E. vesicularis the ventral side of sheath is usually darkened along its length, resulting in an elongate yellowish spot instead of a band. This colour pattern is not always reliable because some E. messene females have the sheaths rather strongly darkened ventrally. Eupelmus messene and E. vesicularis also have shorter ovipositor sheaths, which is evident when examining a specimen (cf. Figs 43 with 44), but it is difficult to quantify using a ratio. Setation of the metasoma, which is much more inconspicuous in E. messene , can help separate E. messene females from E. barai and most E. vesicularis (see under this species). There are also minor differences in the mesotarsal peg patterns of females of the E. vesicularis complex. Eupelmus messene and E. barai have usually four pegs on the posterior margin in the basal half of the basitarsomere, while E. vesicularis and E. balcanicus have three. The apical peg on the posterior margin of the same tarsomere is absent in most or all individuals of many populations of E. messene , as in Romania and Moldova ( Fig. 80 ), but this peg is present in many specimens from North America ( Fig. 81 ). The same peg is present in most females of E. barai ( Fig. 79 ) and this can help to separate them from E. messene in areas where the peg is absent in the latter species. In E. vesicularis , specimens with ( Fig. 83 ) or without a peg have similar frequencies. In E. barai and E. balcanicus the pegs on the anterior margin of the basitarsus are differentiated into two medially overlapping rows ( Figs 78, 79 ), while in E. messene and E. vesicularis they are frequently arranged in a single row ( Figs 81, 83 ), although sometimes they are similarly arranged as for the first two species ( Fig. 80 ) (see also under comparative diagnosis for E. barai and E. vesicularis ).

Biology: Polyphagous species, but frequently associated with hosts in stems of grasses such as the Hessian fly and the jointworms (see host records under results). I have seen specimens reared from four insect orders. Coleoptera : Curculionidae : C e u t o r h y n ch u s a s s i m i l i s (Pa y k u l l). D i p t e r a: Cecidomyiidae : Asphondylia verbasci (Vallot) , Mayetiola destructor (Say) . Hymenoptera : Braconidae : Apanteles sp. ; Cynipidae : Andricus caputmedusae (Hartig) , A. kollari (Hartig) , A. quercuscalicis (Burgsdorff) , Aulacidea hieracii (Bouché) , A. pilosellae (Kieffer) , A. tragopogonis (Thomson) , Aylax hypecoi (Trotter) , Barbotinia oraniensis (Barbotin) , Biorhiza pallida (Olivier) , Diastrophus mayri Reinhard , D. rubi (Bouché) , Iraella luteipes (Thomson) , Iraella ionescui Pujade-Villar & Schiopu , Isocolus scabiosae (Giraud) , Phanacis centaureae Förster , Timaspis lampsanae (Perris) , Xestophanes potentillae (Retzius) , X. szepligetti Balas ; Diprionidae : Neodiprion sertifer (Geoffroy) ; Eurytomidae : Tetramesa brevicollis (Walker) , T. brevicornis (Walker) , T. eximia (Giraud) , T. fulvicollis (Walker) , T. hyalipennis (Walker) , T. linearis (Walker) , T. longula (Dalman) , T. schlechtendali (Hedicke) , Tetramesa spp. Lepidoptera : Tischeriidae : Tischeria ekebladella (Bjerkander) ; Tortricidae : Grapholita delineana Walker ; Yponomeutidae : Yponomeuta malinellus Zeller.

Distribution: A cosmopolitan species. Most likely originally Palaearctic but introduced due to human transport to other biogeographic regions ( Bouček, 1977; Gibson, 1990; both as E. vesicularis ) (see discussions under the heading Thelytokous parthenogenesis and establishment of alien species). The only record of this species under the name Eupelmus messene is that from New Zealand (type locality). Here it is newly recorded from 30 countries and territories (see under non-type material examined), but for many of them the species was previously mentioned as E. vesicularis . Species of the Eupelmus vesicularis complex were never recorded from the Afrotropical region but here E. messene newly recorded for the Neotropics ( Argentina and Colombia).

It is a common species in Europe in dry grasslands, but is absent from Northern Europe except for two aberrant records from Kent ( UK) where it was probably accidentally introduced. Although the distribution data are certainly biased due to large collections in NHMV for Eastern Austria, HNHM for Hungary, AICF for East Romania, and IPPM for Moldova, the species seems especially frequent in the Pannonian region and in the Eurasian Steppe ( Fig. 124 ) that starts in Eastern Romania and stretches through Moldova and Ukraine to Siberia. It frequently shares the same habitat with E. barai .

Remarks: Eupelmus messene Walker, 1839 was described from a female collected in New Zealand by Charles Darwin and synonymized with E. vesicularis by Bouček (1988). The species must have been introduced to New Zealand before 1835 because Darwin visited the islands on 22–30 December 1835 ( Darwin, 1845). The type of E. messene is lost ( Bouček, 1988), but its identity can be inferred from the original description. The given size (c. 2.8 mm) shows that it cannot be a small and lighter coloured female of the other two common species, E. barai or E. vesicularis , and the mentioned reddish-brown colour clearly indicates it as the available name for the widespread thelytokous species. Also, this is the only species of vesicularis complex present in New Zealand. In order to stabilize the application of the name, a neotype is designated below for Eupelmus messene .

Eupelminus coleopterophagus : The species was described from four specimens on two tags ( Girault, 1916). I received from USNM two of the syntypes on one triangular card point. Of these one is uncontorted, lacks the gaster, and has the tips of the antennae gnawed by booklice (paralectotype). The other one is contorted but is otherwise entire and is here designated as lectotype. Examination of the type material and the original description, which mentions the metallic green luster with many parts of the body reddish and the broad silvery band at the base of the metasoma, as well as the type locality, undoubtedly support it is a synonym of E. messene .

Theocolax canadensis : The lectotype of T. canadensis is badly damaged, with only part of the mesosoma and gaster remaining ( Burks, 1963), but the brownish-red body and testaceous legs mentioned in the original description ( Provancher, 1883) as well as the type locality indicate beyond doubt that it is a synonym of E. messene .

Type material examined: NEW ZEALAND: Neotype ♀ of Eupelmus messene Walker with the labels: New Zealand MB / Pelorus Bridge / 4. Mar. 1981; J.S.Noyes / Mixed Podocarpus / Nothofagus ; Macroneura vesicularis (Retz.) / Bouček det. 1986; NEOTYPE; Eupelmus messene Walk. Det. Fusu L. 2008 ( BMNH). USA: Lectotype ♀ of Eupelmus coleopterophagus Girault (present designation) with the labels: St. Paul / Minn.; Type No. / 19947 / U. S. N. M.; Eupelmus / coleopterophagus / Girault. ♀ types; ♀ near pin Lectotype; Paralectotype; Lectotype Eupelmus coleopterophagus Gir. Det. Fusu L. 2014 ( USNM). Paralectotype ♀, on the same point with the lectotype ( USNM).

Non-type material: Austria ( AICF, BMNH, NHMV), Azores ( Portugal) ( LUZN), Bulgaria ( AICF, BMNH, HNHM, PUPB / IBER), Czech Republic ( CNC, NHMV), Czechoslovakia without other locality data ( BMNH), France ( BMNH, CNC, GDCO, MNHN), Greece ( AICF), Hungary ( AICF, BMNH, CNC, HNHM, LUZN), Italy ( BMNH, CNC, LUZN), Madeira ( Portugal) ( AICF), Moldova ( CNC, IPPM), Portugal ( BMNH), Romania ( AICF, ANCO, CNC), Serbia ( HNHM), Spain ( AICF), Switzerland ( CNC, G D C O), U k r a i n e (C N C), a n d U n i t e d K i n g d o m ( England) ( AICF, RRAC).

Extralimital material: Argentina ( AICF), Colombia ( CNC), Australia, New Zealand ( BMNH), Canada ( AICF, CNC, HNHM, LUZN), USA ( BMNH, CNC, LUZN), Armenia ( HNHM), China ( BMNH), Iran ( CNC), Japan ( CNC), Korea ( HNHM, CNC), Kyrgyzstan ( AICF), Russia (Primorsky Krai) ( CNC), Turkey ( CNC). See Appendix 1.

Figures

Figure 17. Size and shape analysis of females in the Eupelmus vesicularis complex using the multivariate ratio analysis (MRA): scatterplot of first against second shape principal component (PC), scatterplot of isosize against first shape PC, PCA ratio spectrum for PC1 and allometry ratio spectrum. Horizontal bars in the ratio spectra represent 68% bootstrap confidence intervals based on 500 replicates.

Figure 124. Distribution map of the species in the Eupelmus vesicularis complex: E. vesicularis (green squares), E. messene (yellow stars), E. balcanicus (blue triangles), E. barai (white circles). Insert: enlarged map of the area with the most dense records (Eastern Austria, Hungary, Romania, and Moldova).

Figures 43–50. Habitus of Eupelmus (Macroneura) species: E. messene ♀ (43), E. balcanicus ♀ holotype (44), E. vesicularis ♀ (45) and ♂ (46), E. muellneri ♀ (47) and ♂ (48), E. vladimiri ♀ (49) and ♂ (50). Scale bars – 1 mm.

Figures 56–67. Mesosoma in dorsal view in Eupelmus (Macroneura) females: E. aseculatus (56), E. rameli (57), E. seculatus (58), E. falcatus (59), E. balcanicus (60), E. barai (61), E. vesicularis clade B from Canada (62), E. vesicularis from Sweden (63), E. messene (64), E. impennis (65), E. maculatus (66), E. vladimiri (67). Scale bars – 0.2 mm.

Figures 96–102. Metasoma in dorsal view in females of: Eupelmus barai from Romania, reared air dried specimen (96), E. vesicularis from Sweden, collected in Malaise trap and chemically dried (97), and E. messene from Romania, reared air dried specimen (98). Detail of setation on the middle of Gt3 in E. barai (99), E. messene (100) and E. vesicularis (101). Reproduction of figure 22 of plate 31 in De Geer’s (1771) book and the empty space in De Geer’s collection showing no pin hole below the label for ‘I. non-ailé à 2 vesſies mobiles T.2 p. 909.’ (102). Scale bars – 0.2 mm for 96–98 and 20 µm for 99–101.

Figures 68–87. Metasoma and mesotarsus in Eupelmus (Macroneura) females: E. rameli (68, 77), E. balcanicus (69, 78), E.barai from Romania (70, 79),E. barai from Spain (71, 82), E.messene (72, 80), E.vesicularis from Sweden (73, 83),E.vesicularis from Slovenia (74), E. vesicularis clade B from Canada (75), E. seculatus (76), E. messene (lectotype of Eupelminus coleopterophagus) (81), E. impennis (84), E. falcatus (85), E. muellneri (86), E. vladimiri (87). Scale bars – 0.2 mm.

Figures 111–123. Details of Eupelmus (Macroneura) morphology. Fore wing rudiment in females: E. barai (111–115), E. rameli (116), E. aseculatus (117), E. messene (118–121). Antenna in males: E. barai (122) and E. vesicularis (123). Scale bar – 0.2 mm. wbL – fore wing base length, waL – fore wing apical part length. Numbers by the wings indicate the size of the specimen.