Lydella Slavonica, a New Species from the Western Palaearctic with Notes on the Subgenus Lydelloxenis (Diptera, Tachinidae) Theo Zeegers
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Tijdschrift voor Entomologie 156 (2013) 103–112 brill.com/tve Lydella slavonica, a new species from the western Palaearctic with notes on the subgenus Lydelloxenis (Diptera, Tachinidae) Theo Zeegers Lydella (Lydelloxenis) slavonica sp. n. is described from Montenegro and Poland. The definition of the subgenus Lydelloxenis Mesnil, 1956 is discussed. A key to western Palaearctic subgenera of Lydella Robineau-Desvoidy, 1830 and species of Lydelloxenis is provided. A phylogenetic analysis for the genus Lydella is provided. The species from the tropics and subtropics are found to form a monophyletic group, called the Metoposisyrops-clade. The species of this clade combined with those of Lydelloxenis are found to form a monophyletic group as well. The results are weakly supported. For practical reasons and nomenclatural stability, Lydelloxenis and Metoposisyrops Townsend, 1916 are proposed as subgenera. Keywords: parasitoids, stem boring caterpillars, phylogeny, Exoristinae, Eryciini. Theo Zeegers, Eikenlaan 24, 3768 EV Soest, the Netherlands. [email protected] Introduction Within the western Palaearctic, the genus Lydella The genus Lydella Robineau-Desvoidy, 1830 is consists of grey tachinids of medium size. The genus known from all major biogeographic regions (O’Ha- is characterized by the bare eye, the erect apical ra 2010). As currently understood, it includes the scutellar setae, presence of one very strong setula subjective synonyms Lydelloxenis Mesnil, 1956 from at base of vein R4+5 and the presence of median the Palaearctic region (Herting 1959) and Dia- discal setae on tergites 3 and 4 (Tschorsnig & Richter traeophaga Towsend, 1916, Metagonistylum Town- 1998). Six species are known (Herting 1984), falling send, 1927 and Metoposisyrops Townsend, 1916 from into two distinct groups. the subtropics and tropics of the old and new world The nomino-typical subgenus consists of four (Woodley 1994). The genus belongs to the tribe species characterized by the presence of fields of spe- Eryciini, of the subfamily Exoristinae (Herting 1960, cialized hairs on the ventral surface of the male fourth Wood 1987, Tachi & Shima 2010). An important tergite (= ‘Sturmia-spots’) (Tschorsnig & Herting feature of this genus is the presence of one very strong 1994), i.e. the type-species L. grisescens Robineau- setula at the base of vein R4+5.AllspeciesofLydella, Desvoidy, 1830 and L. ripae (Brischke, 1885), L. as far as known, are parasitoids of stem boring cater- stabulans (Meigen, 1824) and L. thompsoni Hert- pillars (Woodley 1994) belonging to several families ing, 1959. The subgenus Lydelloxenis,inwhichthese of Lepidoptera, especially Noctuidae and Pyralidae specialized hairs are lacking, consists in the western (Herting 1960), several of them of economic im- Palaearctic of two members: its type-species L. brevi- portance (Cleare 1939, Holloway & Mathes 1940, seria (Pandellé, 1896) and L. lacustris Herting, 1959. Herting 1959). The host choice is a synapomorphy This paper adds a third species: L. slavonica sp. n. for the genus (Woodley 1994). from Montenegro and Poland. Members of the sub- genus Lydelloxenis are very rarely collected. Tijdschrift voor Entomologie 156: 103–112, Tables 1–3. Figs 1–22. [ISSN 0040-7496]. brill.com/tve © Nederlandse Entomologische Vereniging. Published by Koninklijke Brill NV, Leiden. Published 15 July 2013. DOI 10.1163/22119434-00002023 Downloaded from Brill.com10/01/2021 10:33:56AM via free access 104 Tijdschrift voor Entomologie, volume 156, 2013 Methods Note: L. matutina Richter, 2003 from Sakhalin, Morphological terminology follows Oosterbroek et Russian Far East, belongs to Lydella (s.s.) but has only al. (2005) and Tschorsnig & Herting (1994). Mea- 2 anterodorsal setae on mid tibia. sures were taken using an Olympus SZ-61 stereo- microscope with an ocular with scale. Photographs Keytothespeciesofthesubgenus were produced with an Olympus SP-500UZ camera Lydelloxenis in the western Palaearctic mounted on a separate phototube on the stereomi- croscope. Composite multi-focal images were pro- 1. Hind tibia with 3 distinct preapical setae, duced by stacking several images using the software the dorsal equal to posterodorsal and an- program CombineZM (Hadley 2007). Phylogenetic terodorsal one. Mid tibia with 2 strong an- relationships have been studied by parsimony ana- terodorsal setae. Facial ridge with setae in lysis, using the computer program TNT 1.1, as de- lowerhalf......................L. breviseria scribed by Goloboff et al. (2008), running on com- – Hind tibia with 2 distinct preapical setae, puter under Windows XP. dorsal one lacking or very small. Mid tibia The acronyms for collections follow Evenhuis with 1–2 anterodorsal setae, the second seta (2012). To these, I add the following: CCBW – per- less than half as long as the first. Facial ridge sonal collection of C. Bystrowski, Warsaw. with setae restricted to lower third or less . 2 2. Katepisternum with 4 setae (Fig. 3). Api- cal scutellar seta as long as scutellum, longer Results than discal scutellar seta (Fig. 7). Third an- × Key to subgenera of Lydella in the western tennal segment slender, more than 4 as Palaearctic long as broad. Basicosta and tegula black. Male: proclinate orbital seta absent (Figs 1, 1. Genal dilation narrow, occupying at most 4). Wing membrane distinctly darkened half of gena, with only 2 rows of hairs along veins (Fig. 11). Claws and pulvilli (Figs 1, 14, 16). Fore and mid tarsus elon- of fore leg longer than fifth tarsal segment × gated, about 1.2 as long as tibia (Fig. 5). (Fig.6)...................L. slavonica sp. n. First posterior intra-alar seta small, dis- – Katepisternum with 3 setae. Apical scutel- tinctly smaller than other intra-alar setae. lar seta shorter than length of scutellum, Notopleuron with 2 setae, otherwise bare or only as long as discal scutellar seta (Fig. 18). at most with 3–4 hairs. Mid tibia with 1–2 Third antennal segment not slender, at anterodorsal setae. Male: Tergite 4 ventrally most 3× as long as broad. Basicosta brown, without fields of specialized hairs (Fig. 10). tegula black. Male: one pair of proclinate Postocular setulae short, nearly straight. orbital setae (Fig. 14). Wing membrane Fronto-orbital plate between frontal setae slightly yellowish, more so at base (Fig. 19). and eye margin with very sparse and short Claws and pulvilli of fore leg distinctly × hairs. Third antennal segment at most 3 shorter than fifth tarsal segment (Fig. 17) aslongassecond........subgenusLydelloxenis ................................L. lacustris – Genal dilation broad, occupying more than half of gena, with 4 or more rows of hairs (Fig. 20). Fore and mid tarsus of normal Description and redescription of species length, not longer than tibia. First poste- of the subgenus Lydelloxenis rior intra-alar seta strong, as strong as other I have added a note on Lydella (Lydelloxenis) intra-alar setae. Notopleuron with 2 setae columbina from the eastern Palaearctic, so that all and at least 5 hairs but usually many more. known species of Lydelloxenis are dealt with. Mid tibia with 3 or more anterodorsal se- tae. Male: Tergite 4 ventrally with a pair of fields of specialized hairs (‘Sturmia-spots’) Lydella (Lydelloxenis) slavonica sp. n. (Fig. 21). Postocular setulae long, distinctly Figs 1–11 curved forward. Fronto-orbital plate be- Lydella (Lydelloxenis) spec. nov. Zeegers 2010: 6. tween frontal setae and eye margin with Lydella (Lydelloxenis) lacustris: Bystrowski 2005: 3 dense, long hairs, increasing in length to- [misidentification]. wards the frontal setae. Third antennal seg- ment at least 3× aslongassecond....... Type material. Holotype: , Montenegro, Skadar- sko Jezero [= Skadar Lake] WSW Podgorica, Vran- ..........................subgenusLydella jina, 42°17 N; 19°08 E, 13.vi.2009, leg. G. Pennards Downloaded from Brill.com10/01/2021 10:33:56AM via free access Zeegers: Lydella slavonica, new species from western Palaearctic 105 Figs 1–11. Lydella slavonica sp. n., male, holotype. – 1, head, lateral view; 2, thorax, dorsal view; 3, ventral half of thorax, lateral view; 4, head, dorsal view; 5, right fore leg: tibia and tarsus, posterior view; 6, right fore tarsus with claws and pulvilli, posterior view; 7, scutellum, lateral and slightly dorsal view; 8, abdomen, dorsal view; 9, abdomen, view obliquely from behind; 10, abdomen, lateroventral view; 11, right wing. & Th. Zeegers. The holotype will be deposited in (CCBW); Poland,Biebrzanski´ NP, Dolny Basen RMNH. Biebrzy, Bagno Ławki, Ambona NFOS,´ 2.vii.2003, Paratypes: Poland,Biebrzanski´ NP, Dolny Tur zycowisko [= sedge marsh] z Comarum palustre i Basen Biebrzy, Gr. Honczarowska, 25.vi.2003, col- Equisetum palustre,leg.C.Bystrowski(SMNS). lected on Equisetum palustre,leg.C.Bystrowski Downloaded from Brill.com10/01/2021 10:33:56AM via free access 106 Tijdschrift voor Entomologie, volume 156, 2013 Description 5× as long as broad and 2.5× as long as second, Male. Body length 9.5 mm. apical end obliquely truncated, so that the dorsal Colouration (Figs 2, 9). Generally black with apex becomes somewhat angular. Arista thickened on some silvery-white pruinescence. Parafacial, gena and basal two-fifths only, second segment nearly twice occiput behind eye silvery white, fronto-orbital plate as long as broad. Vibrissa at oral margin, setulae slightly yellow, frontal vitta black. Antenna black, above vibrissa small, ascending on lower third of fa- palpus black with yellow tip. Two to three irregular cial ridge. Prementum short (difficult to see), labella rows of black