Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels Author Gosik, Rafal Department of Zoology and Nature Protection, Maria Curie-Sklodowska University, Akademicka 19, 20 - 033 Lublin, Poland Author Skuhrovec, Jiri Group Function of Invertebrate and Plant Biodiversity in Agro-Ecosystems, Crop Research Institute, Prague 6 - Ruzyne, Czech Republic https://orcid.org/0000-0002-7691-5990 jirislavskuhrovec@gmail.com Author Caldara, Roberto Center of Alpine Entomology, University of Milan, Via Celoria 2, 20133 Milan, Italy Author Tosevski, Ivo CABI, Rue des Grillons 1, 2800 Delemont, Switzerland & Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia text ZooKeys 2020 939 87 165 http://dx.doi.org/10.3897/zookeys.939.50612 journal article http://dx.doi.org/10.3897/zookeys.939.50612 1313-2970-939-87 B239701148884712880E1069C943AD33 DB6D50A55057576896F6AFDAE5BC9922 Mecinus collaris Germar, 1821 Material examined. 26 L3 larvae and 21 pupae, Serbia, Zavojskojezero, Pirot, 15.07.2017, GPS 43°12.508'N , 22°35.590'E , 675 m., ex Plantago media , lgt. I. Tosevski . Accession numbers of sequenced specimen MN992001. Description of mature larva (Figures 16A-D , 17A-F ). Measurements (in mm). Body length: 2.00-3.66. Body width (metathorax): 0.80-1.16. Head width: 0.56-0.66. Body (Figure 16A-D ) light yellow, slender, curved, slightly pressed dorso-ventrally. Premental sclerite, pedal lobes and spiracular area of meso- and metathorax dark pigmented. Chaetotaxy of thoracic segments relatively well developed, setae capilliform, variable in length, light yellow, on thoracic segments medium or relatively long, on abdominal segments I-IX short or medium. Prothorax (Figure 16B ) with eleven prns (six long and one short placed on premental sclerite), next three close to spiracle; two medium ps and one short eus. Meso- and metathorax (Figure 16B ) with one medium prs , three medium pds of equal length, one medium as , three medium ss , equal in length, one long eps , one long ps and one short eus. Pedal area with three pda , long or medium. Abdominal segments I-VIII (Figure 16C, D ) with one short prs , four short pds arranged along the posterior margin, two minute ss , one short eps , one short ps , one short lsts and two short eus. Abdominal segment IX (Figure 16D ) with three short ds , all located close to posterior margin, one short ps and two rather short sts. Anal lobes without setae. Figure 16. Mecinus collaris mature larva, habitus and chaetotaxy A habitus of the body and frontal view of the head B lateral view of thoracic segments C lateral view of abdominal segment I D lateral view of abdominal segments VII-X. Abbreviations: Th. I-III - number of thoracic segments, Abd. I-X - number of abominal segments, setae: as - alar, ds - dorsal, eps - epipleural, eus - eusternal, lsts - laterosternal, pda - pedal, pds - postdorsal, prns - pronotal, prs - prodorsal, ps - pleural, ss - spiracular, sts - sternal, ts - terminal. Head capsule (Figures 16A , 17A-C ) dark brown, slightly narrowed bilaterally. Des1-3,5 long, des4 short; des4 located in the central part of epicranium. Fs1 long, fs3 very short, fs4,5 equal in length, almost as long as des1 . Les1 and les2 slightly shorter than des1 ; two ves , and four pes very short (Figure 17A ). Antennae (Figure 17B ) with conical, elongated sensorium (Se), three times as long as wide, and two sensilla basiconica and two sensilla ampullacea. Clypeus (Figure 17C ) trapezium-shaped, anterior margin almost straight; cls1-2 medium, equal in length; clss well visible. Labrum (Figure 17C ) narrow, trapezium-shaped, anterior margin distinctly sinuate; lrs1 long, lrs2 and lrs3 medium. Epipharynx (Figure 17D ) with three elongated, finger-like als of equal length; two medium, straight ams ; two short finger-like mes ; surface smooth; labral rods very short, close to kidney-shaped. Mandibles (Figure 17E ) conical, rather wide; both mds capilliform, medium, equal in length, placed transversely. Maxilla (Figure 17F ) with one stps and two pfs of equal length; mbs short; mala with six long rod-like dms of almost equal size, five vms various in length. Maxillary palpi: basal palpomere distinctly wider and slightly shorter than distal. Prelabium (Figure 17F ) cup-like with one long prms ; ligula with two minute ligs , premental sclerite well developed, with elongated median part. Labial palpi two-segmented; basal palpomere wider and shorter than distal. Postlabium (Figure 17F ) with short pms1 , long pms2 , and short pms3 . Figure 17. Mecinus collaris mature larva, head and mouth parts A head, frontal view B antenna C clypeus and labrum, dorsal view D epipharynx E left mandible F maxillolabial complex, ventral aspect. Abbreviations: at - antenna, clss - clypeal sensorium, des - dorsal epicranial, lr - labral rods, sa - sensillum ampullaceum, sb - sensillum basiconicum, Se - sensorium, st - stemmata, setae: als - anterolateral, ams - anteromedial, cls - clypeal, dms - dorsal malar, fs - frontal, ligs - ligular, lrs - labral, ls - lateral epicranial, mbs - malar basiventral, mds - mandibular, mes - median, mxps - maxillary palp, pes - postepicranial, ves - ventral, pfs - palpiferal, pms - postlabial, prms - prelabial, stps - stipal, vms - ventral malar. Description of pupa (Figure 18A-C ). Measurements (in mm). Head width: 0.30-0.36. Body width: 0.76-1.20. Body length: 1.66-2.33. Body moderately elongated, light yellowish. Rostrum moderately stout, about 2.1 times as long as wide, reaching up to mesocoxae. Antennae relatively short. Pronotum 1.6 times as wide as long. Mesonotum distinctly shorter than metanotum. Urogomphi (ur) short, conical, with sclerotised, sharp apex, slightly reaching outline of the body, directed downward (Figure 18A-C ). Chaetotaxy sparse, setae short, unequal length. Head with only one sos. Rostrum with one rs. Setae on head and rostrum straight, much shorter than those on prothorax (Figure 18A ). Pronotum with two as , one sls , one ls , one ds and four pls. Dorsal parts of meso- and metathorax with two setae placed medially. Dorsal parts of abdominal segments I-IV without setae; segments V-VII with five setae ( d1 placed anteromedially, d2-4 posteromedially, d5 posterolaterally, under spiracle); segment VIII with four setae dorsally. Abdominal segments I-VIII with four long setae ventrally, distributed in regular lines. Abdominal segment IX with two micro-setae ventrally, and next two on urogomphi. Figure 18. Mecinus collaris pupa habitus and chaetotaxy A ventral view B lateral view C dorsal view. Abbreviations: Th. I-III - number of thoracic segments, Abd. I-IX - number of abdominal segments, ur - urogomphi, setae: as - apical, d - dorsal, ds - discal, fes - femoral, l , ls - lateral, pls - posterolateral, rs - rostral, sls - superlateral, sos - superorbital. Biological notes. Larvae feed on various species of Plantago , but mainly on P. media L. and P. maritima L. Plantago lanceolata , P. coronopus L., and P. major L. are also known as host plants. The adults are active from mid-spring following the growth of the flowering stems of the host plant. The female oviposits inside the upper parts of the flowering stem that are covered with floral spikes, which induces clearly visible oblong galls. Very often, several larvae develop in a single flowering shoot. The larvae pupate inside the galls and the adults emerge during summer. Overwintering takes place in the soil litter near the host plant. Remarks. This species, which is widely distributed in the Palearctic region except in North Africa ( Alonso-Zarazaga et al. 2017 ), is unique in Mecinus , being characterised by long elytra and whitish to orange, wide scales covering the base of the pronotum, the epimera and the episterna. For the differences from the immatures of the other species, see the remarks for the group.