Pegomya meridiana Villeneuve 1923

1. Pegomya meridiana (Villeneuve, 1923)

Figs. 1–12.

‘ Pegomyia (Pegomyia) minuta (Meigen) ’; Schnabl & Dziedzicki 1911: 112, figs. 321, 322 and 816. Misidentification, not Anthomyia minuta Meigen, 1826.

Chortophila (Phorbia) meridiana Villeneuve 1923: 94.

Chortophila meridiana Villeneuve; Séguy 1923: 130.

Chortophila (Nudaria) nigrifrons Karl 1928: 171; Karl 1929: 279.

Hylemyia (Nupedia) nigrifrons (Karl); Karl 1937: 138.

Hylemyia meridiana (Villeneuve); Séguy 1937: 103.

Pegomyia hyperici Collin 1947: 34.

Pegomya hyperici Collin; Lyneborg 1965: 254; Coe 1968: 128.

Pegomya meridiana (Villeneuve); Hennig 1973b: 598, text figs. 516–520, pl. figs. 788, 875 and 936; Suwa 1986: 50, figs. 53–65; Barták et al. 1989: 317; Barták et al. 1990: 441, 447; Gorodkov et al. 1995: 8; Pont 1995: 82; Darvas 2001: 400; Michelsen & Barták 2001: 459; Petersen 2001: 185; Michelsen & Báez 2002: 201; Ackland & Merz 2003: 210; Michelsen 2004; Komzáková et al. 2006: 369.

Description. Size. Very small; wing length 2.8–3.4mm.

Male. Head (except lower frons to varying extent ochre yellow in teneral individuals), body and legs brownish black to black, covered in dark greyish brown dusting allowing a faint dark subshine on thorax and abdomen. Antenna black except scape and pedicel sometimes of ochre or light brown colour; prementum mat, covered in thin dusting. Mesonotal pattern of three darker stripes only indicated well in front of transverse suture; abdomen with a mid-dorsal dark stripe interrupted at hind margins of tergites II–V. Wing and calypteres dark brown infuscated; knob of halter greyish black.

Frons at narrowest point 1.5–2.0 times as wide as anterior ocellus; frontal vitta at this point at least 3 times as wide as one parafrontal, yet markedly widened downwards. Orbital- and interfrontal setulae absent, 3–5 equal-sized frontal setae on lower half of parafrontal. Face short, in profile lying well behind fronto-parafacial angle; parafacial inflexed on lower part, in middle about 0.7 times as wide as postpedicel; gena in profile broad, convex at lower margin, with setae arranged in single row. Postpedicel about 1.7 times longer than broad, rounded apically; arista with short pubescence. Proboscis short, unremarkable; palpus longer than prementum.

Mesonotal ground-setulae sparse, absent between dorsocentral rows. Rows of presutural acrostichals closer to each other than to adjacent dorsocentral rows; 2–3 pairs of presutural acrostichals of about same size. Lateral posthumeral seta long; prealar seta less than half length of posterior notopleural seta, sometimes indiscernible from mesonotal ground setulae. Proepisternals 2, proepimerals 2(–3); katepisternals (1–)2+2. Vein C setulose ventrally at least on middle third, entirely bare dorsally. Lower calypter nearly of same size as upper calypter.

Fore tibia with 0 p-seta; mid tibia with 1 ad-, 1 pd- and 0–1 p-seta; hind tibia with 1(–2) av-, 1–2(–3) ad- and 1–2 pd-setae. Mid femur without av-setae but with 3–4 long pv-setae on basal third; hind femur with short av- and pv-setae on basal two-thirds and a few stronger av-setae on distal third.

Abdomen relatively short, depressed, moderately thickened caudally. Tergites III–V without discal setae. Tergite VI bare; spiracles VII present in synsclerite VII+VIII (Figs. 3, 4). Sternite V (Figs. 1, 2) and genitalia (Figs. 5–8) distinctive.

Female. Apart from primary sexual differences similar to male, but different as follows: Thorax covered in a lighter grey dusting leaving no indication of a darker striping pattern on anterior mesonotum; dark greyish dusting on abdomen thin and uniform, leaving no pattern but a distinct dark subshine. Wing faintly greyish brown tinged; calypteres greyish white; knob of halter to varying extent dark greyish tinged.

Frons broad, parallel-sided with frontal vitta about three times as wide as each parafrontal, without pair of crossed setae or setulae; parafrontal with 3 orbital setae followed by 2–3 frontal setae. Vein C ventrally setulose on basal two-thirds or more. Abdominal tergite V longer than tergite IV but shorter than tergites III+IV; spiracles V and VI (Fig. 9) both situated in lateral margins of tergite V. Oviscapt (Figs. 10–12) when fully extended about same length as remaining abdomen, strongly modified: Tergites VI–VIII large, folded roof-like along membranous mid-line, posteriorly with broad bands of very short, mainly proclinate setulae. Sternites VI–VII narrow, each carrying a pair of posterior setae and some very short setulae at margins; sternite VIII very reduced, not distinctly longitudinally divided, with some short setulae. Epiproct folded rooflike and acutely pointed, covered in short, reclinate setulae; hypoproct also laterally compressed, bearing minute setulae but without usual cuticular pubescence. Cerci short, blade-like, adpressed but not fused together apico-dorsally, only with some minute setulae and sensilla along distal margin. Three spermathecae small and globular, as in P. provecta (Fig. 23).

Material examined. ANDORRA [ZMUC]: Pto de Envaliva, 42.35N 1.40E, 1400m, meadow nr. wood, 1 female 8.vii.1990 (M. Barták). CZECH REPUBLIC [ZMUC]: Central Bohemian Region: Kunice, 49.56N 14.40E, 410m, damp meadow, 1 male 30.vi.1984, 1 female 5.vii.1984 (M. Barták); Milčice, 50.07N 14.59E, 200m, nr. pond, 1 female 17.vi.1988 (M. Barták). South Bohemian Region: Vráž u Písku, 49.23N 14.08E, 400m, damp meadow, 1 male 3.vi.1992, 4 males 31.v.1993, 1 male 3.vi.1993, 1 male 30.v.1994, 1 male 2.vi.1994 (M. Barták). DENMARK [ZMUC]: S Jutland (SJ): Gammelpøl, 54.52N 10.04E, <5m, 1 female 1.vii.1973, 1 female 20.vii.1973, 1 female 8.vii.1976 (V. Michelsen); Sandbjerg Gods, 54.57N 9.45E, <10m, 1 female 24.vi.1960 (L. Lyneborg). E Jutland (EJ): Kalø Hestehave, 56.17N 10.27E, <10m, 3 males, 1 female 28, 29.vi.1974 (V. Michelsen); Egsmark Strand, 56.13N 10.39E, <5m, 1male 29.vi.1974 (V. Michelsen); Bønnerup Strand, 56.31N 10.43E, <20m, 1 male 10–21.vii.1991 (S. Andersen). NW Jutland (NWJ): Nors, Ørgaard, 57.02N 8.36E, <30m, 1 female 21.vi.1960 (L. Lyneborg). NE Jutland (NEJ): Saeby, 57.19N 10.31E, <25m, 1 male, 3 females vii.1881 (H.J. Hansen); Trend Skov, 56.49N 10.13E, <30m, 1 male 10–15.vii.1983 (S. Andersen). Funen (F): Ulstrup Mose, 55.26N 10.14E, <20m, 1 male 25.vi.1871 (R.W. Schlick). NW Zealand (NWZ): Jyderup, 55.39N 11.23E, <50m, 1 male 25–30.vi.1977 (Andersen & Michelsen). NE Zealand (NEZ): Bognaes, 55.40N 12.02E, <5m, 1 male 16.vi.1987 (V. Michelsen); Ganløse Orned, 55.49N 12.17E, <50m, 1 female 7.viii.1987 (V. Michelsen); Utterslev Mose, 55.43N 12.30E, <20m, 1 male, 2 females 25.vi.1974, 1 male 20.v.1984 (V. Michelsen); Hareskov, 55.46N 12.23E, <60m, 1 male 10.vii.1982 (S. Andersen); Rude Skov [as Ruderhegn], 55.50N 12.27E, 40–80m, 1 female 29.vi.1884 (H.J. Hansen); Melby Overdrev, 56.01N 11.59E, <10m, 1 male 25.vi.1980 (S. Andersen); Nyrup Hegn, 56.00N 12.32E, <60m, 1 male 7.vii.1984 (S. Andersen). Lolland (LFM): Guldborg Storskov, 54.51N 11.41E, <20m, 1 male 9.vii.1964 (N.M. Andersen). Bornholm (B): Bagå, 55.09N 14.42E, <10m, 1 male 19.vi.1964 (Lyneborg, Martin & Pedersen); Allinge, 55.16N 14.47E, <50m, 2 males, 2 females vii.1883 (H.J. Hansen); Almindingen, 55.06N 14.53E, 100–160m, 1 female vii.1883 (H.J. Hansen); Ekkodalen, 55.06N 14.54E, <100m, Malaise trap, 1 male 3–7.vii.1989 (O. Martin); Rø, 55.12N 14.53E, <110m, 1 female, vii.1883 (H.J. Hansen); Slotslyngen, 55.16N 14.45E, <80m, 2 males 30.vi–10.vii.1981 (S. Andersen); Tejn, 55.14N 14.50E, <20m, 1 male, 1 female 22.vi.1965 (Martin & Pedersen). FINLAND [ZMUC]: Tavastia australis (Ta): Vihti, Moksjärvi, 60.28N 24.25E, <100m, 1 female 1–7.vii.1976 (O. Martin). GREECE [ZMUC]: Central Macedonia: Mt. Olympus, 900–2100m, 2 males 17–20.v.1994 (V. Michelsen). Epirus: Mt. Peristéri, 1200–2100m, 1 male 24– 28.v.1994 (V. Michelsen). RUSSIA [FMNH]: Karelia: Kenjärvi, 62.07N 30.00E, <50m, 1 male 7.vii.1942 (L. Tiensuu). SLOVAKIA [ZMUC]: Bratislava Region: Pernek, 48.21N 17.09E, 240m, damp valley, 1 female 22.vii.1989 (M. Barták). SPAIN [ZMUC]: Lérida: Tremp, 42.10N 0.53E, 470m, 2 males, 1 female 12.vii.1981 (V. Michelsen); Gavàs, 42.38N 1.09E, 1400m, 1 male 13.vi.2002 (V. Michelsen). Gerona: Queralps, 42.20N 2.09E, 1250m, 1 male 13–17.vi.1982 (Andersen, Lyneborg & Michelsen). SWEDEN [MZLU, ZMUC]: Skåne (SK): Osby, Åbrolla, 56.26N 14.08E, 142m, 1 female, 24.vii.2008, 1 female 28.vii.2008 (V. Michelsen). Blekinge (BL): Eringsboda, 56.26N 15.22E, <120m, 1 male, 1–10.vii.1977 (S. Andersen). Småland (SM): Hallaryd, 57.18N 13.54E, <175m, 3 male, 2 females 26.vi–8.vii1983 (V. Michelsen); Eriksmåla, 56.43N 15.28E, <200m, 1 female 21.vii–2.viii.1985 (Andersen & Michelsen). Öland (ÖL): Torslunda, 56.37N 16.31E, <40m, 1 male 8.vi.1977 (B.G. Svensson). Västergötland (VG): Sandhem–Mullsjö, 57.57N 13.47E, <280m, 1 male, 7 females 11–24.vii.1987 (V. Michelsen). TURKEY [ZMUC]: Izmir: Samsun Daġı, 37.39N 27.02E, <200m, 3 males 24–26.iv.1993 (V. Michelsen). UZBEKISTAN [ZMUC]: Zeravshan res., 39.38N 67.08E, 740m, deciduous wood, 2 males 24.v.1989 (M. Barták); Karamazar, 41.30N 69.49E, 800m, alpine meadow, 1 male 18.v.1989 (M. Barták).

Other material (teste D.M. Ackland). CROATIA [Coll. D.M. Ackland]: Lovranska Draga, 1 male, 1 female 11.vi.1981 (D. M. Ackland). KAZAKHSTAN [Coll. D.M. Ackland]: Kara-Tau Mts, 35 km NNE Kentau, 1200– 400m, 2 males 11–12.v.1994 (B. Merz). KYRGYZSTAN [Coll. D.M. Ackland]: Kara-Arthsa Tal, 35 km ESE Dzhanboul, 1 male 4.v.1994 (B. Merz).

Distribution. A very widespread but apparently somewhat local Eurasian species ranging from the British Isles to Japan. The distribution in Fennoscandia is apparently limited to the southern provinces of Sweden and Finland. EUROPE: Andorra (Michelsen & Báez 2002); Croatia; Czech Republic (Hennig 1973b; Barták et al. 1990; Komzáková et al. 2006); Denmark (Lyneborg 1965, Petersen 2001); Finland (Michelsen 2004); France (Villeneuve 1923); Great Britain (Collin 1947, Pont 1995); Greece (Michelsen 2004); Hungary (Darvas 2001); Italy (Gorodkov et al. 1995); Macedonia (Coe 1968); Poland (Karl 1928, 1929, 1937); Russia: Karelia (Michelsen 2004); Slovakia (Barták et al. 1989); Spain (Michelsen & Báez 2002); Sweden (Michelsen 2004); Switzerland (Ackland & Merz 2003). NEAR EAST: Turkey. CENTRAL ASIA: Kazakhstan; Kyrgyzstan; Uzbekistan. EAST ASIA: Japan (Suwa 1986). Presently recorded for the first time from Croatia, Turkey, Kazakhstan, Kyrgyzstan and Uzbekistan. A record from Slovenia (Michelsen 2004) has not been confirmed.

Biology. A series of male and female Pegomya meridiana has been reared in England ex larvae infesting seed capsules of Hypericum perforatum L. (Collin 1947; Pont 1995). Some Finnish occurrences of P. meridiana lie north of the distributional range of H. perforatum and suggest that other species of Hypericum, notably H. maculatum Cranz, serve as host plants.

Biological control. Common St. John’s wort, Hypericum perforatum L. (Clusiaceae), is a perennial herb native to Eurasia and northern Africa, but has been extensively introduced to temperate climatic zones elsewhere in the world. Notably in North America and southeast Australia this plant, which is toxic to cattle and sheep, has become naturalized in pastures and open woodland as an invasive weed displacing forage plants. Several insect enemies are being used with variable success in the attempt to control alien populations of Hypericum perforatum, notably some shoot tip feeding chrysomelid beetles, Chrysolina hyperici (Forster, 1771) and C. quadrigemina (Suffrian, 1851), a stem- and root boring buprestid beetle, Agrilus hyperici (Creutzer, 1799), a defoliating geometrid moth, Aplocera plagiata (Linnaeus, 1758), a sap sucking aphid, Aphis chloris Koch, 1854, and a gall forming cecidomyiid midge, Zeuxidiplosis giardi (Kieffer, 1896). It might be worth testing if this spectrum of control agents should even be supplemented with Pegomya meridiana (Villeneuve, 1926) as a seed-feeding enemy of common St. John’s wort.