Miarus abnormis Solari, 1947

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 : 49-54

Miarus abnormis Solari, 1947 Figures 51, 52, 53-54, 55-56, 57, 58-60

Material examined.

5 L3 larvae: north-eastern Italy, Venezia Giulia, Duino (Trieste), Rilke path, August 2017, ex galls on capsules of Campanula pyramidalis L., leg. E. Tomasi, all collected in association with adults, det. R. Caldara.

Description.

Measurements (in mm). Body length: 3.50-4.75 (mean 3.9). Body width (abdominal segment II) up to 1.65. Head width: 0.57-0.65 (mean 0.60).

General. Body moderately elongated, rather stout, curved, rounded in cross section (Fig. 51).

Colouration. Almost black head (Fig. 51). All thoracic and abdominal segments from greyish-white to yellowish; prodorsum with brownish dorsal sclerite; all abdominal segments covered with fine spiculation (Fig. 51).

Vestiture. Setae on body thin, brown, rather short or minute, piliform.

Head capsule (Fig. 52). Head oval, slightly flattened laterally. Endocarinal line present and very distinct. Stemma placed below des5. Des1-3 and des5 long; des4 medium size (Fig. 52). Fs1 long; fs2 absent; fs3 and fs4 medium size; and fs5 long (Fig. 52). Les1 and les2 as long as des5; one ves very short. Epicranial area with three pes (in line with des2), and also two sensilla.

Antennae located at the end of the frontal suture on each side, membranous and distinctly convex basal article bearing one conical sensorium, relatively elongated; basal membranous article with four sensilla (styloconica) equal in length, and one (ampullacae) (Fig. 53).

Clypeus (Fig. 55) trapezium-shaped, approximately 3.3 times as wide as long with two medium size, equal in length cls, and one sensillum (clss) between setae; all very close to margin with frons; anterior margin of clypeus rounded to inside.

Mouthparts. Labrum (Fig. 55) 2.5 times as wide as long, with three piliform lms, lms1 twice longer than (equal in the length) lms2 and lms3; all located more or less anteromedially, all reach labral margin; anterior margin double sinuate. Epipharynx (Fig. 56) with three medium sized finger-like als, all similar in length; with two rather short, different in length ams; and one medium size, finger-like mes; labral rods (lr) distinct, kidney-shaped. Mandibles (Fig. 54) distinctly broad, bifid, teeth of unequal height; slightly truncate; cutting edge with a blunt tooth; bearing with two setae in short size, piliform, and aligned longitudinally. Maxilla (Fig. 57): stipes with long stps, two long pfs, one minute mbs and two sensillae close to mbs; mala with six finger-like dms (first and second elongated, forth to sixth medium size); five vms (two medium size and three very short); all vms shorter than dms. Maxillary palpi with two palpomeres; basal palpomere with one short mxps and two sensilla; length ratio of basal and distal palpomeres almost 1:1; distal palpomere with one sensillum and a group of microcuticular processes apically. Prelabium (Fig. 57) oval-shaped, with one medium prms; ligula with sinuate margin and three minute ligs; premental sclerite narrow, ring-shaped, well visible. Labial palpi with one palpomere (partially seems as two palpomere); palpomere with one sensillum and medium, cuticular apical processes. Postlabium (Fig. 57) with three pms, all located laterally; pms1 and pms3 short, pms2 medium size; membranous area basolaterally finely asperate.

Thorax. Prothorax smaller than meso- and metathorax. Spiracle bicameral, placed between the pro- and mesothorax. Prothorax (Fig. 58) with ten prns (two minute and eight long), well pigmented dorsal sclerite with four long prns); two medium ps; and one short eus. Meso- and metathorax (Fig. 58) with one short prs, three medium pds; one medium as; two medium and one minute ss; one medium eps; one medium ps; and one very short eus. Chaetotaxy of metathorax (Fig. 58) almost identical to that of mesothorax. Each pedal area of the thoracic segments with six medium length pda (four of them placed on well-separated pedal areas, next two setae outside).

Abdomen. Abdominal segments I–VII (Figs 59, 60) with one short prs; three medium size pds (equal in length); one medium and one minute ss; two medium eps; one medium ps; one medium lsts; and two very short eus. Abdominal segment VIII (Fig. 60) without prs; three medium pds; one medium and one minute ss (sometimes absent); two medium eps; one medium ps; one medium lsts; and two very short eus. Abdominal segment IX (Fig. 60) with three medium ds; one relatively long ps; and two short sts. Abdominal segment X (Fig. 60) without seta.

Biology.

The only detailed biological data are reported by Tomasi (2002), who observed that this species lives in Friuli-Venezia Giulia (Italy) on Campanula pyramidalis L., where larvae cause a distinct swelling of the calix of the flowers, which remain closed.

Remarks.

This species has a well-delimited distribution (south-eastern Poland, Austria, north-eastern Italy, Slovenia, Croatia, Serbia, Montenegro, Macedonia). It is easily distinguishable from all other species of Miarus by the shape of the body of the penis, which is characterized by the presence of two lateral flanges at its apex. However, for the external morphology, the M. abnormis adults are very similar to several other species, such as M. ajugae and M. campanulae , from which they can be distinguished only by the characters of the male ventrite five (fovea less deep, teeth less robust). Unfortunately, the females of these three species appear not to be distinguishable ( Caldara 2007), and the molecular fragment COI poorly differentiates these species. Therefore, the differences between the immatures of these species are much important for the separation of these three species. According to the larval morphology, M. abnormis appears more closely related to M. ajugae than to M. campanulae due to several features (mala with six finger-like dms, different in length: two setae elongated, and four setae of medium length; epipharynx with 1-2 mes, and finally des4 and fs3 present), confirming what was suggested by the adult morphology ( Caldara 2007). Moreover, larvae of M. abnormis differ from other Miarus species here studied mainly by an epipharynx with one finger-like mes.