Mecinus pyraster (Herbst)

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 : 52-54

29. Mecinus pyraster (Herbst)

Figs 27 , 74-75 , 129 , 150 , 165

Curculio pyraster Herbst, 1795: 252 .

Mecinus pyraster (Herbst) . Tournier, 1874: 40. Bedel, 1885: 148; 1887: 311; 1923: 72. Desbrochers des Loges, 1893: 56. Rey, 1894: 74. Reitter, 1907: 9. Hustache, 1931: 404, 406. Hoffmann, 1958: 1267, 1271. Angelov, 1971: 117, 118. Smreczyṅski, 1976: 25. Lohse & Tischler, 1983: 261.

Curculio semicylindricus Marsham, 1802: 294 .

Mecinus schneideri Kirsch, 1870: 392 . Desbrochers des Loges, 1893: 57. Reitter, 1907: 10 (syn. n.).

Mecinus sublineellus Faimaire, 1880: 27 . Reitter, 1907: 10. Escalera, 1914: 470. Hoffmann, 1958: 1272.

Mecinus andalusicus Faust, 1890: 331 . Reitter, 1896: 17; 1907: 10.

Mecinus echinatus Desbrochers des Loges, 1893: 56 . Reitter, 1896: 17; 1907: 10. Hustache, 1941: 5. Hoffmann, 1958: 1271. Mecinus hariolus Reitter, 1907: 9 (syn. n.).

Mecinus pici var. favarcqui Pic, 1915: 27 (syn. n.).

Mecinus pyraster var. piliferus Normand, 1937: 270 . Hoffmann 1958: 1272.

Type locality. Berlin ( Germany).

Type series. This species was described from specimens collected in Germany. We examined three males and one female of these ( ZMHB): one male is labelled “54626 / pyraster Hbst., Berol. ” (lectotype here designated), whereas the other three syntypes do not bear labels (paralectotypes) .

Synonyms. We have not found syntypes of Curculio semicylindricus ( United Kingdom). Therefore we follow the opinion of previous authors, who have always considered this taxon as synonyms of M. pyraster .

M. schneideri was described from specimens collected near Ramleh ( Egypt), of which we examined five syntypes labelled respectively: “ Kirsch, 1870. type / Mecinus Schneideri m., Egyptus / Schneideri” ( NHMW; female, lectotype here designated); “ Schneideri Kirsch type” (Desbrochers des Loges' collection, MNHN; female paralectotype); “Egyptus, Kirsch / type / Typus” ( SMTD; male paralectotype); “Male / Egyptus, Kirsch / Cotypus” ( SMTD; male paralectotype); “Female / Egyptus, Kirsch / Cotypus” ( SMTD; female paralectotype). They differ from the usual specimens of M. pyraster only by their denser elytral vestiture, which is more highly raised. Therefore we include these specimens within the range of variability of M. pyraster .

Mecinus sublineellus Fairmaire was described from specimens collected at Alger. As quoted by Hoffmann (1958), they are only small and narrow specimens of M. pyraster .

We examined three female syntypes of M. andalusicus : one (SMTD) labelled “Andalus., Reitter / andalusicus Faust / Coll. Faust, Ankauf 1900 / type” (lectotype here designated); the second (HNHM) labelled “ Andalusia / Andalusien / Holotypus, 1890. Mecinus andalusicus Faust [arbitrarial museal designation] / Coll. Reitter” and the third as the second except “ Paratypus ” (paralectotypes). This taxon was considered to be a distinct species from M. pyraster by Reitter (1907), but not by Hoffmann (1958). We agree with the latter opinion.

Mecinus echinatus was described from females from Algeria (without more precise indications) and Morocco ( Tanger). We examined one syntype (Desbrochers des Loges' collection, MNHN) labelled “ Algérie / echinatus” (lectotype here designated). Reitter (1907) considered this species as synonymous with M. andalusicus , whereas Hoffmann (1958) synonymized it with M. pyraster . We agree with Hoffmann's opinion.

Mecinus hariolus was described from a single male specimen from Samarcand ( Turkmenistan), which we examined in Reitter' collection (HNHM). There are no noteworthy differences between this species and M. pyraster .

The variety favarcqui of M. pici (synonymous with M. comosus , see below) was described from specimens from Algeria (Philippeville) and must be considered as a subspecies according to Art. 45.6.4 of ICZN (1999). We examined one female syntype labelled “Philippeville, mai / type / TYPE / pici v. Favarcqui Pic” (lectotype here designated). It is only a immature specimen of M. pyraster .

Normand (1937) described the variety piliferus of M. pyraster from specimens from the eastern Pyrenees (Collioure, St. Genis) that must be considered as a subspecies according to Art. 45.6.4 of ICZN (1999). The author quoted that this taxon differs from the nominal form by the scales of the elytral vestiture being uniformly arranged and erect. Since we have not examined syntypes, we follow Hoffmann (1958) who included this taxon within the range of variability of M. pyraster .

Redescription. Male. Length 2.7 mm. Body: long, cylindrical, moderately stout ( Fig. 27 ). Rostrum: black with reddish apex, moderately long (Rl/Pl 0.73), subcylindrical; in lateral view moderately curved, weakly narrowed in basal third ( Fig. 74 ); in dorsal view with subparallel sides, with hardly visible scrobes, distinctly striate-punctured to near apex, in basal half with recumbent, sparse, whitish, moderately long to long (lu /la 4– 8), seta-like scales. Head: frons as wide as rostrum at base, with deep fovea; eyes weakly convex, with hind margin abruptly raised from surface of head. Antennae: black with basal part of scape which is reddish, inserted just in front of middle of rostrum; scape moderately long, 4.5x longer than wide; funicle distinctly longer than scape, segment 1 2.5x longer than wide, weakly stouter and twice as long as segment 2, which is 1.5x longer than wide, segments 3–5 gradually more transverse; club moderately long, oval, with segment 1 about as pubescent as others. Pronotum: black, with dense and regular punctures, intervals between punctures smooth and shining, clearly visible between recumbent, sparse, greyish white, long (l/w 8–10), seta-like scales; moderately transverse (Pw/Pl 1.27), with weakly rounded sides, widest in basal third, with weakly prominent apical constriction, moderately convex. Elytra: black with brownish apex; long (El/Ew 1.63), at base moderately concave, slightly wider than pronotum (Ew/Pw 1.12), with parallel sides, somewhat convex on disc; interstriae clearly visible between recumbent to subrecumbent, sparse, whitish and greyish brown, long to very long (0.75–1.00x as long as width of interstria; l/w 8–12), seta-like scales, arranged in 2–3 irregular rows and more adpressed on interstria 1; striae clearly visible, one third narrower than interstriae, with a row of whitish scales slightly shorter than those of interstriae. Legs: stout, with recumbent to suberect, sparse, whitish, seta-like scales, which are distinctly shorter than width of tibia; femora black, with stout tooth; tibiae black, moderately stout; protibiae with apical part of ventral surface somewhat directed outward; unci black, stout, all equal in length; tarsi reddish brown, tarsomere 1 1.3x longer than wide, tarsomere 2 about as long as wide, tarsomere 3 bilobed and distinctly wider than tarsomere 2, onychium as long as tarsomeres 1–3 taken together; claws brown, equal in length, fused in basal half. Venter: metasternum black, clearly visible between recumbent to suberect (midline), sparse, whitish, hair-like scales; mesothoracic epimera and meso- and metathoracic episterna with somewhat dense, whitish, long scales; abdomen black, with dense and somewhat regular punctures, which are clearly visible between subrecumbent to suberect, moderately dense, whitish, long, seta-like scales, with a tuft of thinner long brownish hair at middle of ventrite 5; ventrites length ratio 1– 2/3–4 1.89. Penis: fig. 129.

Female. As in male except rostrum longer (Rl/Pl 0.93) ( Fig. 75 ), smooth and shining, sparsely and finely punctured, antennae inserted just before middle of rostrum, femora with indistinct tooth. Sternite 8: fig. 150. Spermatheca: fig. 165.

Variability. Length 2.3–3.2 mm. The body varies distinctly in length and width (El/Ew 1.55–1.70). The colour of the elytral integument varies from completely black to reddish in the apical part. Sometimes the elytral scales are erect and distinctly variable in number.

Remarks and comparative notes. This species is very common and widespread in the Palaearctic region. It is distinctly variable in size, shape of the body and in the vestiture within the same population. Some of the numerous taxa considered here as synonymous with M. pyraster seem to be at the extremes of the range of variability, either for the features of the vestiture ( Mecinus schneideri ) or the shape of the body ( M. sublineellus ). However, in spite of its great variability, this species is usually easily distinguishable from similar taxa like M. sicardi and especially M. baridioides , to which it is closely related because ventrite 5 in the male bearing a median tuft of hairs and the unusual shape of the spermatheca (see comparative notes for these species).

Biological notes. Larvae feed on floral spikes, collars, stems and roots of Plantago lanceolata L., without producing visible external deformations, and P. media L., where they induce fusiform galls ( Hustache 1931; Hoffmann 1958). Adults of M. pyraster were also collected on P. lagopus L. in Spain and Malta ( Sprick 2001). This species also exhibits cases of singular allotrophy, since larvae were observed to grow and pupate in galls of Rhodites rosae L. ( Hymenoptera, Cynipedae ), and in the sporiferous layer of the poliporous fungus Phellinus fulvus (Scop.) Pat. ( Hoffmann 1958) .

Distribution. Palaearctic region except Japan. Imported in northern America ( O'Brien & Wibmer 1982). We examined also a specimen collected in the Afrotropical region ( Democratic Republic of Congo, Ituri, Nduye).

Non-type specimens examined. About 800 specimens collected in United Kingdom, Portugal, Spain, France, Switzerland, Italy, Malta, Germany, Russia, Czech Republic, Slovakia, Hungary, Croatia, Serbia, Greece, Bulgaria, Romania, Turkey, Morocco, Algeria, Tunisia, Egypt, Israel, Syria, Iran, Turkmenistan, Congo .

Figures

FIGURES 19–27. Habitus of (19) Mecinus henrici; (20) M. elongatus; (21) M. alternans; (22) M. tanaiticus; (23) M. reichei; (24) M. humeralis; (25) M. circulatus; (26) M. suturalis; (27) M. pyraster. Not to the same scale.

FIGURES 69–77. Rostrum in lateral view of (69) Mecinus tanaiticus, male; (70) idem, female; (71) M. humeralis, female; (72) M. circulatus, male; (73) idem, female; (74) M. pyraster, male; (75) idem, female; (76) M. baridioides, male; (77) idem, female. Scale bar = 0.5 mm.

FIGURES 121–132. Penis in dorsal and lateral view of (121) Mecinus desertorum; (122) M. marina; (123) M. henrici; (124) M. alternans; (125) M. reichei; (126) M. tanaiticus; (127) M. circulatus; (128) M. humeralis; (129) M. pyraster; (130) M. comosus; (131) M. simus; (132) M. pirazzolii. 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.