Mecinus dorsalis Aubé, 1850

Caldara, Roberto & Fogato, Valter, 2013, Systematics of the weevil genus <i> Mecinus </ i> Germar, 1821 (Coleoptera: Curculionidae). I. Taxonomic treatment of the species, Zootaxa 3654 (1), pp. 1-105 : 76-77

45. Mecinus dorsalis Aubé

Figs 40 , 94–95

Mecinus dorsalis Aubé, 1850: 343 . Bedel, 1885: 148; 1887: 311. Desbrochers des Loges, 1893: 57. Reitter, 1907: 9. Hustache, 1931: 403, 406. Hoffmann, 1958: 1267, 1273.

Mecinus dorsalis var. alpinus Hustache, 1941: 5 . Hoffmann, 1958: 1273.

Type locality. Le Mans (northern France).

Type series. This taxon was described from a single specimen, which we did not find. However, based on the original description we agree with the sense usually attributed to this species ( Hoffmann 1958).

Synonyms. The variety alpinus was described from specimens collected at Col d'Allos (Basses-Alpes) at 2200 m. Hoffmann (1958) synonymized this variety with M. dorsalis , specifying however that it might be a mountain subspecies. We examined six syntypes of this taxon (MNHN), all labelled “Col d'Allos, 22.VII.36”; moreover one male is also labelled “Type / dorsalis v. alpinus m.”. We designated the last one as lectotype and the other specimens as paralectotypes. We have not observed differences between these specimens and specimens of M. dorsalis collected at low altitude.

Redescription. Male. Length 2.3 mm. Body: long, cylindrical, slender ( Fig. 40 ). Rostrum: black, moderately long (Rl/Pl 0.85); in lateral view distinctly and abruptly curved in basal half, weakly narrowed in apical half ( Fig. 94 ); in dorsal view with subparallel sides, weakly widened at antennal insertion, with hardly visible scrobes, weakly striate-punctured, without punctures along midline, in basal half with recumbent, sparse, white, moderately long (l/w 3–6), seta-like scales. Head: frons as wide as rostrum at base, with moderately deep fovea; eyes nearly flat, with posterior margin abruptly interrupted. Antennae: black, inserted at middle of rostrum; scape moderately short, 3.5x longer than wide; funicle distinctly longer than scape, segment 1 twice as long as wide, slightly stouter and slightly longer than segment 2, which is 1.5x longer than wide, segments 3 and 4 about as long as wide, segment 5 transverse; club long, oval, segment 1 about as pubescent as others. Pronotum: black, with dense and regular punctures, intervals between punctures smooth and shining, clearly visible between recumbent, moderately dense, brownish grey and white, the latter more numerous along midline and sides, long (l/w 5–8), seta-like scales; weakly transverse (Pw/Pl 1.19), with weakly rounded sides, with moderately prominent apical constriction, widest in basal third, moderately convex. Elytra: black, somewhat shining; very long (El/Ew 1.70), at base moderately concave, with parallel sides, slightly wider than pronotum (Ew/Pw 1.28), moderately convex on disc; interstriae clearly visible between recumbent to subrecumbent, moderately dense, white, 0.75–1.00x as long as width of interstria (l/w 5–8), seta-like scales, arranged in a single regular row; striae clearly visible, one third narrower than interstriae, with a row of scales similar to shorter ones covering interstriae. Legs: moderately slender, with recumbent to subrecumbent, sparse, whitish, seta-like scales, which are distinctly shorter than width of tibia; femora black, pro- and mesofemora with stout tooth, metafemora with smaller tooth; tibiae black, moderately slender; protibiae with apical part of ventral surface weakly directed outward; unci blackish, stout, all equal in length; tarsi blackish brown, tarsomere 1 1.5x longer than wide, tarsomere 2 about as long as wide, tarsomere 3 distinctly bilobed and distinctly wider than tarsomere 2, onychium shorter than tarsomeres 1–3 taken together; claws brown, fused at base, asymmetrical, with one claw distinctly smaller and about half shorter than other claw. Venter: metasternum black, clearly visible between sparse, whitish, long, seta-like scales; mesothoracic epimera and meso- and metathoracic episterna with sparse, white, narrow seta-like scales, and fringed wide scales; abdomen black with bronze reflexions, with dense and somewhat regular punctures, which are clearly visible between sparse, whitish, long, seta-like scales; ventrites length ratio 1–2/3–4 1.72. Penis: as in M. tavaresi ( Fig. 143 ).

Female. As in male except rostrum slightly longer (Rl/Pl 1.08) ( Fig. 95 ), less punctured, antennae inserted just before middle of rostrum, femora unarmed. Sternite 8 and spermatheca: as in M. heydenii ( Figs 156 and 170 ).

Variability. Length 1.9–2.6 mm. The scales of the dorsal vestiture vary from whitish to almost transparent light brown, and sometimes are arranged at least in part in two rows on some elytral interstriae. Specimens from Greece and Bulgaria differ from the typical French specimens by the integument having bronze reflections and the rostrum being less abruptly curved.

Remarks and comparative notes. This species is reported here for the first time from Greece and Bulgaria, records which considerably widen the distribution area of this species, previously known from a few localities from southern France ( Hoffmann 1958). However due to the subtle morphological differences and the apparent distribution gap from the western specimens, those from Greece and Bulgaria might represent a different taxon. Mecinus dorsalis is closely related to M. tavaresi with which it shares the shape of the terminalia both in the male and in the female. It differs from this species by the rostrum being more abruptly curved at base, the elytra shorter, and the scales on the elytral interstriae being recumbent. It may also be confused with M. aubei , whose integument is more shining, with bronze reflections, and whose elytra are distinctly longer and narrower.

Biological notes. In France larvae feed on the collar and roots of various species of Linaria ( L. simplex (Willd.) DC. , L. supina L., L. thymifolia DC. , L. tourneforti Poir. ), where they produce globose galls ( Hoffmann 1958).

Distribution. France, Greece, Bulgaria.

Non-type specimens examined. FRANCE: Île de France, Trappes , 26.IV.1942, Ruter leg. (1, MNHN) ; Languedoc-Roussillon, Pyrénées-Orientales, Millas , bord du Têt, 13.VI.1974, Péricart leg. (1, MNHN) ; Loire, La Varenne, V.1900, on Linaria supina (5, MNHN) ; Seine-et-Marne , Champigny (1, MNHN) ; Seine-et-Marne, Lagny, Hustache leg. (4, DEIM; 6, MNHN; 8, MSNM); Seine-et-Marne , Lesches , 29.IX.1932 (8, MNHN) . GREECE: Macedonia, Halkidiki, Gerakini, Leiler leg. (1, DEIM) . BULGARIA: Strandzha, 2 km from village Kosti , 20.VI.1974 (1, MMCT) ; Rodopi, Severoiztočni, Kalojanci , 16.VI.1982, Košťál leg. (1, JFCH) ; Jasna Poliana , S of Burgas, 27.V.1995, Białooki leg. (1, PBCS) .

Figures

FIGURES 37–42. Habitus of (37) Mecinus barbarus; (38) M. lixoides; (39) M. heydenii; (40). M. dorsalis; (41) M. tavaresi; (42) M. aubei. Not to the same scale.

FIGURES 88–97. Rostrum in lateral view of (88) Mecinus kaemmereri, female; (89) M. setulosus, male; (90) M. janthinus, male; (91) idem, female; (92) M. barbarus, male; (93) idem, female; (94) M. dorsalis, male; (95) idem, female; (96) M. tavaresi, male; (97) idem, female. Scale bar = 0.5 mm.

FIGURES 133–143. Penis in dorsal and lateral view of (133) Mecinus vulpes; (134) M. pipistrellus; (135) M. collaris; (136) M. lixoides; (137) M. sicardi; (138) M. janthiniformis; (139) M. barbarus; (140) M. janthinus; (141) M. heydenii; (143) M. tavaresi; (142) M. aubei. Scale bar = 0.2 mm.

FIGURES 144–156. Sternite 8 of (144) Mecinus pascuorum; (145) M. caucasicus; (146) M. marina; (147) M. reichei; (148) M. humeralis; (149) M. circulatus; (150) M. pyraster; (151) M. simus; (152) M. collaris; (153) M. janthinus; (154) M. lixoides; (155) M. sicardi; (156) M. heydenii. Scale bar = 0.2 mm.

FIGURES 157–171. Spermatheca of (157) Mecinus pascuorum; (158) M. caucasicus; (159) M. haemorrhoidalis; (160) M. labilis; (161) M. marina; (162) M. elongatus; (163) M. reichei; (164) M. circulatus; (165) M. pyraster; (166) M. simus; (167) M. comosus; (168) M. lixoides; (169) M. janthinus; (170) M. heydenii; (171) M. collaris. Scale bar = 0.2 mm.