Cleopomiarus distinctus (Boheman, 1845)

Skuhrovec, Jiri, Gosik, Rafal, Caldara, Roberto, Tosevski, Ivo, Letowski, Jacek & Szwaj, Ewelina, 2018, Morphological characters of immature stages of Palaearctic species of Cleopomiarus and Miarus and their systematic value in Mecinini (Coleoptera, Curculionidae, Curculioninae), ZooKeys 808, pp. 23-92 : 27-30

Cleopomiarus distinctus (Boheman, 1845) Figures 1, 2, 3-4, 5-6, 7, 8-10

Material examined.

17 L3 larvae: 7 exx., 29.07.2010, Gródek ad Hrubieszów, CE Poland, leg. E. Szwaj, det. J. Łętowski; 10 exx., ex seed capsules of Campanula cervicaria L., 05.07.2017, Stara Planina, Babin Zub, east Serbia, leg. I. Toševski, all collected in association with adults det. R. Caldara. Accession numbers of sequenced specimens: MH558546.

Description.

Measurements (in mm). Body length: 4.43-5.57 (mean 4.90). Body width (metathorax or abdominal segments I–II) up to 1.37. Head width: 0.70-0.84 (mean 0.71).

General. Body elongated, slender, curved, rounded in cross section (Fig. 1).

Colouration. Black head (Fig. 1). All thoracic and abdominal segments from distinctly white to slightly yellow (Fig. 1).

Vestiture. Setae on body thin, light yellow to greyish, distinctly different in length (minute to very long).

Head capsule (Fig. 2). Head oval, slightly flattened laterally. Frontal sutures distinct, seem as pallid stripes. Anterior stemma (st), in the form of a small pigmented spot. Des1-3 and des5 long; des4 short (Fig. 2). Fs1 long; fs2 absent; fs3 very short; fs4 long; and long fs5 (Fig. 2). Les1 and les2 as long as des5; both ves medium to very short. Epicranial area with three pes and two sensilla in line with des2.

Antennae bearing one relatively elongated conical sensorium; and basal membranous article with four sensilla equal in length, and two pores (Fig. 3).

Clypeus (Fig. 5) approximately three times as wide as long with two cls of medium size, equal in length, and one sensillum; anterior margin sinuate.

Mouthparts. Labrum (Fig. 5) almost two times as wide as long, with three piliform lms, almost equal in the length; all located more or less anteromedially, lms2 and lms3 distinctly reach labral margin. Epipharynx (Fig. 6) with three medium sized finger-like als, all similar in length; with two rather short, equal in length ams; and one medium size, finger-like mes; labral rods (lr) distinct, elongated, slightly convex. Mandibles (Fig. 4) bifid; cutting edge with a blunt tooth; bearing with two setae in medium size, piliform, and aligned longitudinally. Maxilla (Fig. 7) stipes with long stps and both pfs, minute mbs, and one sensillum close to mbs; mala with six medium sized finger-like dms; five vms, three medium size, two very short. Maxillary palpi: basal palpomere with one short mxps and two sensilla; distal palpomeres with medium, cuticular apical processes; length ratio of basal and distal palpomeres 1:1. Prelabium (Fig. 7) with one short prms; ligula with one minute ligs; premental sclerite narrow, ring-shaped. Labial palpi with two palpomeres; length ratio of basal and distal palpomeres 1:1.2; each of the palpomeres with one sensillum, distal palpomeres with medium, cuticular apical processes. Postlabium (Fig. 7) with long pms1 located basally, very long pms2 located medially and long pms3 located apically; membranous area basolaterally sparsely and finely asperate.

Thorax. Prothorax (Fig. 8) with nine very long prns, weakly pigmented dorsal sclerite present with six long prns, this sclerite subdivided in two triangular plates medially; two long ps; and one short eus. Meso- and metathorax (Fig. 8) with one medium prs, three long pds; one long as; two very long and one minute ss; one long eps; one long ps; and one very short eus. Each pedal area of the thoracic segments with five very long pda.

Abdomen. Abdominal segments I–VII (Figs 9-10) with one medium prs; one long and two medium size pds (order: medium, long, medium); one very long and one minute ss; two very long eps; one medium ps; one medium lsts; and two very short eus. Abdominal segment VIII (Fig. 10) with one very short to minute prs; one short and two long to relatively long pds (order: short, long, relatively long); one long and one minute ss; two very long eps; one medium ps; one medium lsts; and two very short eus. Abdominal segment IX (Fig. 10) with four short ds; one medium ps; and two short sts. Abdominal segment X (Fig. 10) without seta.

Biology.

This species lives on various species of Campanula ( C. glomerata L., C. incurva Auch., C. latifolia L., C. persicifolia L., C. rapunculus L., C. rhomboidalis L., C. thyrsoides L., C. trachelium L.) in central Europe ( Hoffmann 1958; Smreczyński 1976; Caldara and Legalov 2016). It was never reported to feed on C. cervicaria L., a species widely distributed in Europe. Larvae are seed feeders developing inside seed capsules.

Remarks.

This is one of the most variable species and with the widest Palaearctic distribution in the genus (Europe and central and northern Asia to the Russian Far East) ( Caldara and Legalov 2016; Jiang et al. 2018). The three most variable characters in adults are the colour of the dorsal vestiture, which varies from whitish grey to light brown, the density of the elytral scales, which sometimes completely cover the integument, and the length of the rostrum, especially in the female and Anatolian populations. It is clear that it would be very interesting to perform a detailed molecular study of these populations. Apart from the characters of the shape of the rostra, the uncus of the male metatibiae and that of the penis, this species differs from C. graminis and related species also by the more angulate shape of the elytral base. Also the immatures of C. distinctus can easily be separated from those of C. graminis by several characters in larvae: postlabium with medium size pms1 and pms3, a very long pms2 (Fig. 7) and a membranous area of postlabium basolaterally finely asperate as well as in pupae: Vs and sos absent (or as microsetae) (Fig. 82), pronotum with one sls (Fig. 83), and abdominal segments I–VII without ventral setae (Fig. 82). Finally, we could confirm that these two species are well separated molecularly as previously reported ( Vahtera and Muona 2006; Hendrich et al. 2015; Horecka et al. 2017).