Description of immature stages of Rhinusa species (Coleoptera, Curculionidae, Mecinini) with a focus on diagnostic morphological characters at the species and genus levels Author Gosik, Rafal https://orcid.org/0000-0002-2083-4905 Department of Zoology and Nature Protection, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka 19, 20 - 033 Lublin, Poland Author Caldara, Roberto https://orcid.org/0000-0001-9932-7078 Via Lorenteggio 37, 20146 Milan, Italy Author Tosevski, Ivo https://orcid.org/0000-0002-3666-3151 CABI, Rue des Grillons 1, 2800 Delemont, Switzerland & Institute for Plant Protection and Environment, Banatska 33, 11080 Zemun, Serbia Author Skuhrovec, Jiri https://orcid.org/0000-0002-7691-5990 Group Function of Invertebrate and Plant Biodiversity in Agro-Ecosystems, Crop Research Institute, Prague 6 - Ruzyne, Czech Republic jirislavskuhrovec@gmail.com text ZooKeys 2024 2024-03-14 1195 1 94 http://dx.doi.org/10.3897/zookeys.1195.112328 journal article http://dx.doi.org/10.3897/zookeys.1195.112328 1313-2970-1195-1 617FBE9C72D1479D83361E9325D74B93 7B852D1F498258A8AC2E473512274E16 9) Rhinusa collina (Gyllenhal, 1813) Material examined. 8 mature larvae; 3 ♂ and 3 ♀ pupae. Serbia , Knjazevac , ex Linaria vulgaris inside R. linariae galls, 05.07.2017 , leg., det. I. Tosevski . Description of mature larva (Figs 41A, B , 42A-E , 43A-C ). Measurements (in mm). Body length: 2.60-3.00 (avg. 2.75). The widest place in the body (meso- and metathorax) measures up to 0.90. Head width: 0.55-0.65 (avg. 0.60). Figure 41. Rhinusa collina (Gyllenhal, 1813) mature larva A habitus B head, frontal view. Figure 42. Rhinusa collina (Gyllenhal, 1813) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at-antenna, lr-labral rods, sa-sensillum ampullaceum, sb-sensillum basiconicum, Se-sensorium, st-stemmata, setae: als -anterolateral, ams -anteromedial, cls -clypeal, des -dorsal epicranial, dms -dorsal malar, fs -frontal epicranial, les -lateral epicranial, ligs -ligular, lrs -labral, mbs -malar basiventral, mds -mandibular dorsal, mes -medial, mpxs -maxillary palp, pes -postepicranial, pfs -palpiferal, pms -postmental, prms -premental, stps -stipital, ves -ventral, vms -ventral malar. Figure 43. Rhinusa collina (Gyllenhal, 1813) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII-X (schemes). Abbreviations: Th. 1-3-number of thoracic segments, Abd. 1-10-number of abdominal seg, setae: as -alar, ds -dorsal, eps -epipleural, eus -eusternal, lsts -laterosternal, pda -pedal, pds -postdorsal, prns -pronotal, prs -prodorsal, ss -spiracular, ps -pleural, sts -sternal. General . Body elongate, slender, distinctly curved, rounded in cross section (Fig. 41A ). Prothorax prominent, pronotal shield not pigmented. Meso- and metathorax equal in size, smaller than prothorax; each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I-VI of similar size, next segments tapering towards posterior body end. Abdominal segments I-VII each divided dorsally into two various in size folds; postdorsal folds much higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I-VII conical. Laterosternal and eusternal folds of segments I-VIII conical, weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in previous segment. Thoracic and all abdominal spiracles unicameral; thoracic spiracles (Fig. 41A ) placed ventrolaterally; abdominal spiracles (Fig. 41A ) placed anteromedially on segments I-VIII. Colouration . Dark yellow to light brown head, medial parts of epicranium less sclerotised (Fig. 41B ). Frons and ventrolateral parts of the head covered with knobby asperities. All thoracic and abdominal segments whitish. Cuticle covered with fine asperities (Fig. 41A ). Vestiture . Setae on body thin, yellowish, different in length (minute to medium). Head capsule (Figs 41B , 42A ). Head suboval, endocarinal line present, reaching to 3/4 length of frons. Frontal sutures on head distinct, very wide. Two pairs of stemmata various in size in the form of small black spots (st); first medium size located close to end of frontal suture, second small placed mediolaterally. Des1 long, located in middle part of epicranium; long des2 ; long des3 located anteriorly on epicranium close to the border with the frontal suture; des4 very short; and des5 elongated, located anterolaterally above stemma (Fig. 42A ). Fs1 and fs2 absent; fs3 minute, located medially; fs4 long, located anteriorly; and long fs5 located anterolaterally, close to antenna (Fig. 42A ). Les1 and les2 medium; and two minute ves . Epicranial area with two pes . Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus three sensilla basiconica and single ampullacea (Fig. 42B ). Clypeus (Fig. 42C ) trapezoidal, ~ 2.7 x as wide as long with two cls : cls1 relatively long, cls2 medium, both localised posterolaterally, with one sensillum between them; basal part distinctly more sclerotised than the apical part; anterior border slightly curved towards the inside. Mouth parts . Labrum (Fig. 42C ) ~ 2 x as wide as long, with three piliform lrs , various length; lrs1 elongated, located posteromedially, lrs2 elongated, located medially, and lrs3 short, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 42C ) with two elongated finger-like als , almost identical in length; two piliform ams equally in length; and single finger-like mes ; labral rods (lr) distinct, close to kidney shape. Mandibles (Fig. 42D ) bifid, cutting edge with a single, blunt protuberance; two medium piliform and single minute mds , all located close to lateral border. Maxillolabial complex: maxilla dark sclerotised (Fig. 42E ), stipes with one stps , two pfs and one mbs and one sensillum, stps and both pfs1-2 relatively long; mala with five finger-like dms variable in length (divided into two groups); four piliform vms , medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of three or four apical sensilla in terminal receptive area. Prementum (Fig. 42E ) oval-shaped, with one long prms ; ligula with slightly sinuate margin and two short ligs ; premental sclerite broad, sclerotised, U-shaped. Labial palpi one-segmented; palpi with a single pore, and a group of two or three apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 42E ) with three pms , elongated pms1 located posteromedially, elongated pms2 located laterally, and medium pms3 located anterolaterally; lateral parts of membranous area covered with distinct knobby asperities. Thorax . Prothorax (Fig. 43A ) with five medium prns : three placed apically, next two above stigma; two medium ps ; and single short eus . Mesothorax (Fig. 43A ) with one minute prs , two short and one medium pds (ordered: short, medium, short); one medium as ; three ss (two medium and one minute); one medium eps ; two medium ps ; and single minute eus . Chaetotaxy of metathorax (Fig. 43A ) almost identical to that of mesothorax. Each pedal area of thoracic segments with three medium and two minute pda . Abdomen . Segments I-VIII (Fig. 43B, C ) with one minute prs (segment VIII without); two minute and one medium pds ; one minute and one medium ss ; one medium eps ; one short ps ; one minute lsts ; and two minute eus . Abdominal segment IX (Fig. 43C ) with two minute ds ; one minute ps ; and two minute sts . Description of pupa (Figs 44A-C , 45A-C ). Measurements (in mm). Body length: 2.70-2.90 (avg. 2.75); body width: 1.75-1.80 (avg. 1.75); thorax width: 1.10-1.25 (avg. 1.15); rostrum length: up to 0.60 ♂ and 0.85 ♀. Figure 44. Rhinusa collina (Gyllenhal, 1813) pupa habitus A ventral view B lateral view C dorsal view. Figure 45. Rhinusa collina (Gyllenhal, 1813) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a-pr-abdominal protuberances, p-pr-pronotal protuberances, ur-urogomphi, setae: as -apical, d -dorsal, ds -discal, fes -femoral, l , ls -lateral, os -orbital, pas -postantennal, pls -posterolateral, sos - supraorbital, v -ventral. Body . Integument white, with some parts dark sclerotised; moderately stout, curved. Head with small head protuberances (h-pr) above eyes. Rostrum elongated, on both sexes almost 4 x as long as wide, distinctly protruding to mesocoxae. Pronotum trapezoidal 2.4 x as wide as long. Pronotal protuberances (p-pr) indistinct, flattened, sclerotised, separated at bases. Meso- and metanotum similar in size. Abdominal segments I-VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with rounded, prominent, sclerotised abdominal protuberance (a-pr). Urogomphi (ur) medium, ending with sclerotised, sharp apexes (Fig. 44A-C ). Chaetotaxy . Well developed, setae medium to elongated, transparent. Head with one medium os and one elongated sos . Rostrum with a single pas (Fig. 45A ). Pronotum with three as , one ds , two ls , and two pls variable in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 45A-C ). Abdominal segments I-VI with four setae dorsally, variable in length: first and third minute, second and fourth medium, placed close to posterior margin of the segment. Abdominal segments VII and VIII with three elongated setae dorsally. Each lateral part of abdominal segments I-VII with a single short seta. Ventral parts of abdominal segments I-VIII with three medium setae. Abdominal segment IX with two short setae ventrally (Fig. 45A-C ). Remarks and comparative notes. This species is widely distributed in Europe ( Alonso-Zarazaga et al. 2023 ). In adults, the shape of the rostrum, together with the moderately elongated body, are useful characters that easily distinguish this species from the others in the group. Biological notes. Rhinusa collina is an inquiline weevil whose development is closely linked to root galls on L. vulgaris and L. genistifolia caused by R. linariae . The females oviposit eggs exclusively on well-developed galls that are not occupied by R. linariae larvae. For this reason, the competition of these inquiline weevils with gall inducers has never been observed (IT, pers. obs.).