Zootaxa 3754 (2): 159 172 www.mapress.com/zootaxa/ Copyright 2014 Magnolia Press Article http://dx.doi.org/10.11646/zootaxa.3754.2.5 http://zoobank.org/urn:lsid:zoobank.org:pub:4fcd8b04-c8cb-441c-93f1-8fd682a47972 ISSN 1175-5326 (print edition) ZOOTAXA ISSN 1175-5334 (online edition) Descriptions of immature stages of the weevil Lixus punctiventris Boheman, 1835 (Coleoptera, Curculionidae, Lixini) RAFAŁ GOSIK 1 & MAREK WANAT 2,3 1 Department of Zoology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland 2 Museum of Natural History, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland 3 Corresponding author. E-mail: wanatm@biol.uni.wroc.pl Abstract Last instar larva of Lixus punctiventris Boheman is redescribed and illustrated, its pupa is described and illustrated for the first time. Biology of this species is analyzed in association with larval morphology and feeding habits. Overall larval and pupal morphological diagnoses of the genus Lixus and larval diagnosis of the tribe Lixini are updated. Key words: weevils, Lixini, Lixus, taxonomy, morphology, chaetotaxy, larva, pupa, bionomics Introduction The knowledge of the morphology of mature larvae of the genus Lixus is based primarily on the recent studies by Nikulina (2001, 2007) and Nikulina & Gültekin (2011), as well as on some older works of Ter-Minassian (1936, 1943), Scherf (1964) and Lee & Morimoto (1988). Scherf (1964) listed the descriptions of larvae of 14 Lixus species, but only 4 of them are at least partially illustrated and can be regarded as detailed. Moreover the pupae have been described (more or less) precisely for only 3 species (Scherf 1964). Most of the hitherto described preimaginal stages are of the species distributed in the Far East or in Central Asia: 9 species (Nikulina 2001) and then 3 more species (Nikulina 2007), while those of the west Palaearctic species are still insufficiently known. Lixus punctiventris Boheman (beetle on figures 1, 4) was for a long time an almost unknown weevil in Poland, with only several mostly old records from southern subregions of the country, and only one discovery after WWII (Burakowski et al. 1993; Stachowiak 1999). In 2011 one of us published results of field studies initiated after discovery of this species in 2005 in the Przedborski Landscape Park, and soon after in the neighbouring Świętokrzyskie Mts (Wanat 2011). The weevil appeared relatively common in both studied areas, which was realized after examination of its primary host plants, i.e. Crepis biennis L. and Picris hieracioides L. The former plant especially revealed approximately 100% presence of the larvae of L. punctiventris in every controlled site. In contrast, adult beetles were invariably found only sporadically using standard collecting methods and even by watching the proper plants specifically. Attempts at sweeping fields of the host plants by night did not bring much better results. The beetles turned out to be dedicated epigeic ground-dwellers, generally avoiding climbing vegetation, even their proper host plants. While the former contribution by Wanat (2011) was focused on general biology and host preferences of L. punctiventris in Poland, in the present study we provide detailed morphological descriptions of mature larva and pupa. Although a larval description of this species can be found in Scherf (1964), we find it insufficient and lacking in a number of characters relevant in Lixini, particularly as regards chaetotaxy. Material and methods Material examined. POLAND: Chęciny, lat/long 50.8127N/20.4573E, 09.07.2007, pupae (1 2 ), larvae (4 mature spec., 1 younger larval instar), leg. M. Wanat. All specimens deposited at collections of Department of Zoology of Maria Curie-Skłodowska University in Lublin. Accepted by R. Anderson: 25 Dec. 2013; published: 14 Jan. 2014 159
Procedures. Larvae and pupae were picked up from their host plants (Figs 2, 3), killed with hot water and fixed in 80% ethanol. The specimens were examined under an Olympus SZ60 optical microscope and camera lucida. Measurements. Measurements were taken from all available specimens using the calibrated oculars and Olympus SZ60 microscope. The following features of each specimen were measured using a calibrated microscopic eyepiece: - Larva: length (BL) from front of the head to end of last abdominal segment (AbX), height (BH) of the body (the latter on the thickest place in lateral view) (see Fig. 5), and maximum width (HW) and length (HL) of the head capsule (see Fig. 17). - Pupa: length (BL) (from apex of head, without protuberances of vertical setae to end of AbIX, without pseudocerci), and the widest place (BW) (between apices of meso-femora in the pupa). Pronotum length in pupa was measured along its mid-line. Illustrations. Drawings were made using a drawing tube installed on an optical microscope and processed by computer programmes (Adobe Photoshop, Corel Photo-Paint 11, Corel Draw 11). Photos were made using Olympus SZX16 microscope and processed by the Olympus Stream Motion software. Adult beetle habitus was photographed using JVC KYF75 camera attached to Leica M205C stereomicroscope; the photo was prepared using the AutoMontage Pro and Photoshop CS2 software. The in situ photos of larva, pupa and adult were taken with the Nikon Coolpix 4500 digital camera. Terminology. Names and abbreviations of general body parts follow terminology proposed by Scherf (1964). Setae are named after May (1994) and setal codes are consistently given in italics. Terms used in descriptions of the mouth parts and antennae are adopted from Marvaldi (1997, 1998). Abbreviations used in text: avg. average (referring to mean value of taken measurements), s. seta. Remaining abbreviations and setal codes used on figures are explained directly in their legends. Results Re-description of mature larva (Figures 5 24) General morphology. All thoracic (Th) and abdominal segments (Ab) I VIII cream-white. AbIX and AbX light yellow. Cuticle (especially on ventral) parts of AbI VIII covered by spine-like cuticular processes. AbVII and AbVIII wholly covered by well visible spine-like processes. Pronotal area of prothorax well isolated, light brown. Body slender, elongate, slightly curved (Fig. 5), round in cross section, at widest place (AbI) (avg.) 2.90 mm; total body length (avg.): 13.3 mm (measurements in Table 1). Prothorax slightly smaller than similar to each other mesoand metathorax. AbI almost as big as metathorax. AbII VII broader than AbI, similar to each other. AbVIII slightly smaller than previously ones. AbIX again distinctly smaller than AbVIII. AbX reduced to four anal lobes: a lateral pair of elongated, situated horizontally, a short dorsal lobe, and very small ventral lobe. Dorsal parts of meso- and metathorax each divided into two lobes. Dorsal parts of AbI VII each divided into three lobes, AbVIII into two dorsal lobes. Lateral folds of AbI VIII rather poorly isolated. Spiracles 9 pairs, bicameral, first pair placed on anterior margin of prothorax, next 8 pairs (AbI VIII) medial. Thoracic spiracle (Fig. 6) rotated 90º left in comparison with abdominal ones (Fig. 7), located laterally, close to posterior margin of prothorax. Chaetotaxy well developed, setae light brown, hairform, varying in size. Each side of prothorax (Figs 8, 11, 14) with 9 prns (pronotal s.) of unequal length (8 long and 1 very short, all located on sclerotized shield) and next 3 short setae distributed near spiracle; 2 similar in length vpls (ventropleural s.) and 2 short msts (mesosternal s.). Mesothorax (Figs 8, 11, 14) on each side with 1 very short prs (prodorsal s.), 5 pds (postdorsal s.) (apical one very short, remaining ones long), 1 as (alar s.), 3 short ss (spiracular s.) 1 long dpls (dorsopleural s.), 1 vpls and 2 msts. Each pedal area of thoracic segments with 8 almost equal in length pda (pedal s.). Chaetotaxy of metathorax (Figs 8, 11, 14) similar to that of mesothorax. AbI VII (Figs 9, 12, 15, 16) on each side with 1 very short prs, 6 different in length pds (ordered along posterior margin of each segment, odd ones short, even ones long), 1 dls, 1 short ss, and paired dpls (different in length) and vpls (almost equal in length), 1 lsts (laterosternal s.) and 2 short msts. AbVIII (Figs 10, 13, 16) on each side with 1 very short prs, 6 different in length pds (ordered along posterior 160 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
FIGURES 1 4. Lixus punctiventris: 1 mounted adult in dorsal view, 2 larva in a root-neck of Crepis biennis, 3 pupa removed from its camera in the same plant species, 4 reared adult put on flower of Hieracium sp. IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 161
FIGURES 5 16. Lixus punctiventris, larva habitus, spiracles and chaetotaxy: 5 habitus, 6 thoracic spiracle, 7 abdominal spiracle, 8, 11, 14 thoracic segments, 9, 12, 15 first abdominal segment, 10, 13, 16 abdominal segments VII X, 8 10 dorsal view, 11 13 lateral view, 14 16 ventral view (BL body length, BH body height, Th n thoracic segment, Ab n abdominal segment, setae: as alar, dls dorsolateral, dpls dorsopleurolateral, ds dorsal, ls lateral, lsts laterosternal, msts mesosternal, pda pedal, pds postdorsal, prns pronotal, prs prodorsal, ss spiracular, sts sternal, ts terminal, vpls ventropleural). 162 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
FIGURES 17 20. Lixus punctiventris, larval head: 17 dorsal view, 18 lateral view, 19 ventral view, 20 antenna, detail (at antenna, st stemma, HL head length, HW head width, setae: des dorsal epicranial, fs frontal, les lateral epicranial, pes postepicranial, ves ventral). IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 163
FIGURES 21 24. Lixus punctiventris, larval mouth parts: 21 labrum and clypeus, 22 epipharynx, 23 mandible, 24 maxillolabial complex, ventral aspect (right side dorsal aspect of maxillia) (lr labral rods, lrm labrum, cl clypeus, mpa maxillary palps, stp stipes, ma mala, lpa labial palp, plb praelabium, plsb postlabium, setae: als anteriolateral, ams anteriomedial, cls clypeal, dms dorsal malar, ligs ligular, lrms labral, mpxs maxillary palp, mbs mala basiventral, mds mandibular dorsal, mes median, pfs palpiferal, plbs prelabial, pslbs postlabial, stps stipal, vms ventral malar). 164 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
margin of segment, odd ones short, even ones long), 1 dls, without ss, paired dpls and vpls (both different in length), 1 lsts (laterosternal s.) and 2 short msts. AbIX (Figs 10, 13, 16) on each side with 6 different in length ds (dorsal s.) located close to posterior margin of segment, 3 different in length ls (lateral s.) and 3 short sts (sternal s.). Each of horizontal anal lobes (AbX) (Figs 10, 13, 16) with 3 very short ts (terminal s.). TABLE 1. A synopsis of basic measurements of seven available larval and pupal specimens of Lixus punctiventris. Abbreviations: HW head width; HL head length; BL body length; BH body height; BW body width. No. HW HL BL BH BW Sex Mature larva 1 1.60 1.45 13.5 3.0 - - 2 1.50 1.40 14.0 2.9 - - 3 1.50 1.45 11.5 2.8 - - 4 1.55 1.50 14.0 2.9 - - Pupa 1 1.60-13.5-5.1 2 1.45-11.4-4.3 3 1.50-13.0-4.2 Head and mouth parts. Head light brown; width (avg.): 1.54 mm, length (avg.): 1.45 mm (measurements in Table 1), slightly oblate bilaterally, frontal suture distinct, Y shaped, endocarina present, reaches 4/5 length of frons. Setae on head hairform, different in length. All des 1-5 (dorsal epicranial s.) equal in length; des 1, des 2 and des 3 located in central part of epicranium, des 4 placed close to frontal suture, des 5 located antero-laterally (Figs 17, 18, 19). Fs 1-5 (frontal s.) different in length, fs 1, fs 2 and fs 4 slightly shorter than fs 3, fs 5 ; fs 1 placed postero-medially, fs 2 medially, fs 3 -fs 5 antero-medially and antero-laterally, close to epistoma. Les 1 -les 3 (lateral s.) equal in length, slightly shorter than des. Two ves (ventral s.) short, poorly observed. Post epicranial area with 3 very short pes (postepicranial s.) (Figs 17, 18). Two pairs of stemmata (st) located laterally and antero-laterally. Antenna small, rounded, located on end of frontal suture; antennal segment with sensorium conical, slightly elongated, located medially; basal membranous article with 5 basiconic sensilliae (Fig. 20). Labrum (lrm) (Fig. 21) approximately 2.0 times as wide as long, with 3 pairs of lrms (labral s.) of different length, close each other in triangle shape; lrms 1 slightly shorter than lrms 2, both 2.0 times longer than lrms 3, all lrms placed on distinct protuberances; anterior margin sinuously emarginate. Clypeus (cl) (Fig. 21) 2.7 times as wide as long, with 2 hairform and equally long cls (clypeal s.), localized postero-laterally; anterior margin of clypeus straight. Epipharynx (Fig. 22) with 5 pairs of bacilliform als (antero-lateral s.) of different length; 3 pairs of slightly elongated ams (antero-medial s.) and 2 pairs of finger-like mes (medial s.). Labral rods (lr) elongated, slightly converging posteriorly. Mandibles (Fig. 23) slightly curved, apically bifid, teeth of unequal length, the cutting edge serrated. Mds 1-2 hairform, equal in length. Maxillary stipes (stp) (Fig. 24) with 1 stps (stipal s.) and 2 equally long pfs (palpiferal s.); mala (ma) with 8 elongated, bacilliform dms (dorsal malar s.) different in length, 3 vms (ventral malar s.) different in length (vms shorter than dms), and 2 very short mbs (malar basiventral s.) different in length. Maxillary palpi (mpa) with two palpomerae, each segment with a pore; basal palpomere 1.5 times longer than distal ones, with short, bacilliform mpxs (maxillary palp s.); distal palpomere at apex without cuticular processes. Praelabium (plb) (Fig. 24) heartshaped, with 1 long plbs (prelabial s.) located medially. Ligula with 2 hairform ligs (ligular s.) of equal length, densely covered by thorn-like cuticular processes. Premental sclerite poorly visible, in a form of incomplete ring. Labial palpi (lpa) two-segmented, each segment with a pore; basal palpomere 2 times longer than distal one; apex of distal palpomere without cuticular processes. Postlabium (pslb) (Fig. 24) with 3 hairform pslbs (postlabial s.), different in length; the first pair localized antero-medially, and remaining two pairs laterally. Description of pupa (Figures 25 27) General morphology. Body length: 11.4 13.5 mm, maximum width at the level of procoxae: 5.1 mm ( ), 4.2 mm ( ), head width: 1.60 mm ( ), 1.50 ( ) (measurements in Table 1). Body elongated, slender, yellowish. Cuticle IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 165
FIGURES 25 27. Lixus punctiventris, pupa, habitus and chaetotaxy: 25 total, ventral view, 25a chaetotaxy of head, 25b detail chaetotaxy of AbVIII IX, 25c ventral part of AbVIII IX (male), 25d ventral part of AbVIII IX (female), 26 total (dorsal view), 26a chaetotaxy of pronotum, 26b detail of ThII, 26c f details of selected abdominal segments, 27 total (lateral view) (pc pseudocerci, Th n thoracic segment, Ab n abdominal segment, setae: as apical, d dorsal, ds discal, fes femoral, l, ls lateral, os orbital, pas postantennal, pls posterolateral, sos super-orbital, sls superlateral, v ventral, vs vertical). 166 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
smooth. Rostrum in female elongated, approximately 3.0 times as long as wide, surpassing mesocoxae in a repose range, in male more stocky, 2.0 times as long as wide, surpassing procoxae. Antennae long and slender. Pronotum nearly as wide as long. AbI short, AbII V of almost equal length, AbVI VII gradually diminished, AbVIII semicircular, AbIX distinctly smaller than the preceding ones. AbIII VII each with 4 pairs, AbVIII with 5 pairs of dark, sclerotized thorn-like protuberances forming a regular transverse row along posterior margin; the thorn-like protuberances gradually increasing in size from AbIII to AbVIII. Pseudocerci very short, triangular, and well sclerotized. Five pairs of functional spiracles on AbI V. Sexual dimorphism visible in the length of rostrum and the structure of AbIX: gonotheca of undivided (Fig. 25c), of divided (Fig. 25d). Chaetotaxy. Setae short, straight, of unequal length, yellow or brown, on rostrum, head and pronotum based on small protuberances. Rostrum with a pair of rs (rostral s.); head capsule bearing 1 vs (vertical s.), 3 sos (superorbital s.), 2 os (orbital s.) and 3 pas (postantennal s.) (Figs 25, 25a); pas 2 slightly shorter than other setae on head and rostrum. Pronotum with: 1 as (apical s.), 1 ds (discal s.), and 2 ls (lateral s.), 2 sls (super lateral s.) and 2 pls (posterolateral s.) (Figs 26, 26a). Chaetotaxy of metathorax as on mesothorax, consisting of 6 pairs of short d (dorsal s.) (Fig. 26b). Tergal parts of AbI II each with d 1-9 located posteriorly and postero-laterally (Fig. 26c); AbIII VII besides sclerotized denticles each with 1 seta located postero-medially, and next 4 setae placed posterolaterally (Figs 26d, 26e). AbVIII with 4 hairform setae (Fig. 26f). AbVII and AbVIII each with two additional setae d 0 placed antero-medially (Figs 26e, 26f). Each of AbI VIII with 2 short l (lateral s.) placed close to the border with tergum (Fig. 27). Sternal parts of each of AbI VIII with 5 v (ventral s.), 3 of them located posteriorly, remaining 2 setae placed laterally (Figs 25, 27). Abdominal dorsal setae gradually increasing in size from AbI to VIII. AbIX with 3 short setae placed close to pseudocerci, and next 3 pairs located dorsally (Fig. 25b). Each femoral apex with 2 fes (femoral s.) of almost equal length (Fig. 25). Discussion Scherf (1964) provided a generalized description of the larva of Lixus punctiventris, which appeared incomplete or misleading according to the standards and terminology established for the weevil immatures by May (1993, 1994). The discrepancies between Scherf's description and our observation are summarized in Table 2. Moreover, Scherf (l.c.) omitted the chaetotaxy of the terminal abdominal segments, relevant for determination of the species of Lixus. Nikulina (2001) provided the up to now most precise description of the larva of the genus Lixus, which can be summarized as the following character set: 1) body C-shaped, 5 14 mm long, round in cross section, cuticular lobes well visible, white or yellowish; 2) head capsule subglobose or oval-shaped, epistoma present, with rounded lateral borders; 3) antenna two-segmented with 1 or more sensillae; 4) clypeus trapeziform with 2 pairs of setae and a pair of sensilliae; 5) anterior margin of labrum straight or sinuous, posterior one rounded, covered by clypeus; 6) tormae well developed, elongated; 7) three pairs of labral setae different in length; 8) mandibles massive, pyramidshaped, well sclerotized, bifid, teeth unequal in size, cutting edge sometimes with accessory tooth; 9) maxilla consists of well sclerotized cardo, stipes, mala and two-segmented maxillary palps; 10) mala on both ventral and dorsal parts with groups of setae; 11) stipes with 3 pairs of well developed setae; 12) postlabium weakly sclerotized, with 3 pairs of symmetrically distributed setae; 13) praelabium cup-shaped, with a pair of setae; 14) ligula broad, rounded, densely covered by thorn-like cuticular processes; 15) pronotum with 6 8 setae on each sclerotized area, and two groups of 3 short setae above spiracle; 16) meso- and metanotum each divided into two lobes, tergal parts of abdominal segments divided into three lobes; 17) pedal area of thoracic segments well isolated, each with 5 8 long setae; 18) spiracles 9 pairs (first seemingly placed on prothorax, remaining ones on AbI VIII); 19) AbX consisting of four anal lobes. The larva of L. punctiventris possesses all these characters listed by Nikulina (2001), with just a few exceptions partly resulting from differences in terminology, e.g. labral rods being more accurate term than "tormae" in the Curculionidae (Marvaldi 2003). According to May (1993) and Marvaldi (1997, 2003) the larvae of most weevils (incl. Lixinae) possess one-segmented antennae, excepting only the families Belidae and Attelabidae. Therefore we regard the first segment described by Nikulina (2001) to be rather a basal retractile membrane of true one-segmented antenna. The group of 3 long stipal setae figured by Nikulina (2001) in our opinion consists actually of one stipal and two palpiferal setae. IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 167
TABLE 2. Number of setae in mature larva of Lixus punctiventris: a Scherf (1964), b present study. PART OF BODY setae a b Prothorax pronotal 10 12 ventropleural 2 2 mediosternal 0 2 pedal 8 8 Meso- Metathorax prodorsal 1 1 postdorsal 5 5 alar 0 1 spiracular 0 3 dorsopleural 2 1 ventropleural 2 1 mediosternal 0 2 pedal 8 8 Abdominal segments I VIII prodorsal I VII 1 1 VIII? 1 postdorsal I VII 5 6 VIII? 6 dorsolateral I VII 1 1 VIII? 1 spiracular I VII 2 1 VIII? 0 dorsopleural I VII 2 2 VIII? 2 ventropleural I VII 2 2 VIII? 2 laterosternal I VII 1 1 VIII? 1 mediosternal I VII 1 2 VIII? 2 Abdominal segment IX dorsal? 6 lateral? 3 sternal? 3 Abdominal segment X terminal? 3 Head capsule dorsal 5 5 frontal 5 5 lateral 3 3 postepicranial? 3 ventral? 2 Clypeus and Labrum clypeal 2 2 labral 3 3 Mandible madibular 2 2 Epipharynx anteriolateral 5 5 anteriomedial 3 3 medial 3 2...continued on the next page 168 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
TABLE 2. (Continued) PART OF BODY setae a b Maxilla lacinia (dorsal) 6 8 lacinia (ventral) 4 3 palpal 2 2 stipital 1 1 palpiferal 1 1 mala basiventral 2 2 Labium postlabial 3 3 prelabial 2 1 ligular 2 2 Among Tadzhik species of Lixus examined and keyed by Nikulina (2001), the only comprehensive larval key available for this genus, the larva of L. punctiventris show most affinities to the larva of L. strangulatus Faust. The differences are presented in Table 3. TABLE 3. Morphological differences between mature larvae of Lixus strangulatus Faust and L. punctiventris Boheman. Lixus strangulatus body length under 11 mm; lateral folds of AbVIII with 3 setae, equal in length; dorsal parts of AbVIII with 4 setae, equal in length ; head with 4 fs, 2 ls; without ves and pes; epipharynx with 3 als; ligula with 2 setae, different in length. L. punctiventris body length over 13 mm; lateral folds of AbVIII with 3 setae different in length; dorsal parts of AbVIII with 6 setae different in length; head with 5 fs, 3 ls, 2 pairs of ves and 3 pes; epipharynx with 5 als; ligula with 2 setae, equal in length. As it could have been expected, the described until now larvae of Lixus (Nikulina 2001, 2005; Nikulina & Gültekin 2011) show perceptible similarity to the larvae of the closely related genus Larinus (Nikulina et al. 2004; Gosik & Skuhrovec 2011). It is manifested primarily in the number, shape and distribution of setae on head, and some parts of abdominal segments, and the shape and chaetotaxy of the mouth parts is almost identical in both genera. The differences between larvae of Lixus and Larinus are diagnosed in Table 4. TABLE 4. Morphological differences between larvae of the species of genera Lixus Fabricius and Larinus Dejean. Lixus body slender; stemmata: mostly 2 pairs; ligula broad, rounded, densely covered by thorn-like cuticular processes; pedal setae mostly equal in length; AbVII and IX (especially on ventral parts) covered with well visible spine-like cuticular processes; Larinus body moderately slender to stocky; stemmata: 1 pair or absent; ligula sinuate, smooth (without thorn-like cuticular processes); pedal setae mostly differing in length; cuticle of AbVII and IX smooth; Based on descriptions of the larvae of five Larinus species (Gosik & Skuhrovec 2011; Nikulina et al. 2004) (except immatures of L. pollinis which chaetotaxy is unique not only in Larinus genus, but also in known larvae and pupae of other weevils) and the larvae of about twenty Lixus species (Ter-Minassian 1936, 1943; Scherf 1964; Lee & Morimoto 1988; Nikulina 2001, 2007; Nikulina & Gültekin 2011) the following compilation of diagnostic characters of the larvae of the tribe Lixini can be proposed: 1) body C shaped, round in cross section; 2) head capsule subglobose or oval-shaped; 3) frontal sutures distinct, Y-shaped, extending to a lower pair of stemmata; 4) endocarina line mostly well indicated; 5) head with 5 pairs of des, 5 pairs of fs, and 2 3 pairs of les (except L. IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 169
strangulatus); 6) antennae one-segmented, each located at the end of frontal suture; sensorium conical, more or less elongated; 7) clypeus trapeziform, mostly with 2 pairs of moderately long cls; 8) epipharynx usually with 5 pairs of als, 3 pairs of ams, and 2 pairs of mes (except L. strangulatus); 9) labral rods well developed, elongated, slightly converging; 10) maxilla with more than 7 dms; 11) praelabium heart shaped or cup shaped, with a pair of long plbs; 12) ligular setae well developed, 2 3 pairs; 13) meso- and metanotum each transversely divided into two lobes (prodorsum with 1 prs, postdorsum with 5 pds, and 1 as); 14) each pedal area well isolated, with more than 5 long pds; 15) each of AbI VII with 5 7 pds, 1 dls, 1 ss, 2 vpls, and 2 msts; 16) AbX reduced to four anal lobes of unequal size, dorsal one by far the largest, ventral one very small. Considering relatively low number of so far described larvae and pupae of Lixini, it is probable that the set of diagnostic features will be changed during further examination. Scherf (1964) in his monumental work on weevil immatures referred to morphology of pupae of eight species of Lixus: (Dilixellus) bardanae (Fabricius), algirus auct. = (Dilixellus) pulverulentus (Scopoli), (Lixus) paraplecticus (Linnaeus), (Eulixus) iridis Olivier, (Compsolixus) junci Boheman, (Epimeces) cardui Olivier, elongatus Goeze = (Epimeces) filiformis (Fabricius), (Dilixellus) punctiventris (Boheman), but only in the case of L. paraplecticus his characterization can be regarded as fully original description supported with original and detailed illustrations allowing for decoding of chaetotaxy to follow current standards. For the remaining seven species he either based on older descriptions and oversimplified illustrations, as for L. punctiventris (Falcoz, 1926), L. pulverulentus (Bodenheimer, 1928), L. junci (Brémond, 1938) and L. filiformis (Mellini, 1950), or did not provide any illustrations and his verbal descriptions are useless. Scherf's (l. c.) views on pupal chaetotaxy of L. paraplecticus and L. punctiventris are confronted with our observation on the pupa of the latter species in Table 5. TABLE 5. Numbers of pupal setae: a Lixus paraplecticus; b L. punctiventris (both after Scherf 1964); c L. punctiventris (present study). PART OF BODY setae a b c Head capsule vertical 2 2 1 super orbital 2 3 3 orbital 1 0 2 post antennal 5 5 3 Rostrum rostral 3 1 1 epistomal 0 1 0 Prothorax superapical 0? 0 apical 2? 1 lateral 5? 2 superlateral 0? 2 discal 3? 1 posterolateral 3? 2 Mesothorax dorsal 6 5 6 Metathorax dorsal 6 5 6 Abdominal segments I VI dorsal 6? 9 ventral 5? 5 lateral 2? 2 Abdominal segments VII, VIII dorsal 6 5 9 ventral 5? 5 lateral 2? 2 Abdominal segment IX ventral 4? 3 dorsal 5? 3 Leg femoral 2? 2 170 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT
After compilation of Scherf's (1964) verified descriptions, primarily of L. paraplecticus, and our present examination of the pupa of L. punctiventris, the following combination of pupal characters can be proposed, as diagnostic for the genus Lixus: 1) body slender, elongate, 2) setae on head, rostrum and pronotum placed on small protuberances; 3) thoracic segments II and III each with 6 dorsal setae (d); 4) AbI VIII each with 5 pairs of ventral setae (v), 2 pairs of lateral setae and 6 9 pairs of dorsal setae; 5) some dorsal setae on AbIII VIII replaced with thorn-like cuticular protuberances; 6) rostrum with 1 3 pairs of rostral setae (rs), and 3 5 pairs of postantennal setae (pas); 7) head with 1 2 pairs of orbital setae (os), 2 3 pairs of super-orbital setae (sos), and 1 2 pairs of vertical setae (vs); 8) pronotum with 1 2 pairs of apical setae (as), 2 5 pairs of lateral setae (ls), 1 3 pairs of discal setae (ds), 2 pairs of superlateral setae (sls), and 2 pairs of posterolateral setae (pls); 9) each femoral apex with 2 setae; 10) pseudocerci very short, triangular, well sclerotized. Regarding chaetotaxy, analogies between pupae of weevil genera Lixus and Larinus are observed only in the number of dorsal setae on meso-, metathorax (6 pairs of setae) and AbI VIII (9 pairs of setae). On the other body parts the number of setae is different in both genera. Moreover, the setae of AbVIII are placed on elongated protuberances in Larinus pupae, while it has not been observed in studied Lixus pupae. Also the shape of pseudocerci is different in both genera: narrow in Larinus, short and triangular in Lixus. However, the very poor knowledge on pupae of Lixini does not allow us to generalize the differences listed above and this diagnosis must be considered as provisional and requiring confirmation based on a larger species number. Number and shape of setae make possible not only recognition of species or genera e.g.: Otiorhynchus (Gosik & Sprick 2012); Lixus (Nikulina 2001, 2007); Bagous (Gosik 2013); Thryogenes (Gosik 2011); Hypera and Donus (Skuhrovec 2004, 2006, 2007); Ceutorhynchus (Nikulina 2008); Mogulones (Gosik 2010). Moreover, studies based on comparisons of chaetotaxy of the larvae provide knowledge of phylogeny of some groups e.g. Bagous (Gosik 2013) and Tychius (Skuhrovec et al. in press). Of course, value of those studies increases proportionately to the number of species for which good descriptions are available. References Bodenheimer, F.S. (1928) Ist Lixus algirus L. ein Schädling. Zeitschrift für Angewandte Zoologie, 13, 477 482. http://dx.doi.org/10.1111/j.1439-0418.1928.tb00052.x Brémond, P. (1938) Recherches sur la biologie de Lixus junci. Revue de Pathologie Végétale et d'entomologie Agricole de France, 25, 59 73. Burakowski, B., Mroczkowski, M. & Stefańska J. (1993) Chrząszcze (Coleoptera), Ryjkowce-Curculionidae, część 1. Katalog Fauny Polski XXIII, 19, 1 306. Falcoz, L. (1926) Matériaux pour l étude des Larves des Curculionides. Annales des Épiphyties, 12, 195 281. Gosik, R. (2010) Description of the mature larvae of four species of the genus Mogulones (Coleoptera, Curculionidae). Deutsche Entomologische Zeitschrift, 57, 203 218. http://dx.doi.org/10.1002/mmnd.201000017 Gosik, R. (2011) Morphology of the developmental stages of Thryogenes festucae (Herbst, 1795) with comments on its biology, Polish. Entomologica Journal, 80, 475 484. http://dx.doi.org/10.2478/v10200-011-0035-y Gosik, R. (2013) Morphology of larval and pupal stages of selected species of Bagoinae THOMSON, 1895 with comments on their biology and taxonomy. Wydawnictwo UMCS, Lublin, 127 pp. Gosik, R. & Skuhrovec, J. (2011) Descriptions of mature larvae and pupae of the genus Larinus (Coleoptera: Curculionidae, Lixinae). Zootaxa, 3019, 1 25. Gosik, R. & Sprick, P. (2012) Morphology and identification of the pupae of seven species of the genus Otiorhynchus Germar, 1822 (Coleoptera, Curculionidae, Otiorhynchini). Zootaxa, 3483, 39 57. Lee, C.Y. & Morimoto, K. (1988) Larvae of the family curculionidae of Japan. Part 2. Hyperinae to Cioninae (Insecta: Coleoptera). Journal of the Faculty of Agriculture, Kyushu University, 33 (1 2), 131 152. Marvaldi, A.E. (1997) Higher Level Phylogeny of Curculionidae (Coleoptera: Curculionoidea) based mainly on Larval Characters, with Special Reference to Broad -Nosed Weevils. Cladistics, 13, 285 312. http://dx.doi.org/10.1111/j.1096-0031.1997.tb00321.x Marvaldi, A.E. (1998) Larvae of Entiminae (Coleoptera: Curculionidae): Tribal diagnoses and phylogenetic key, with a proposal about natural groups within Entimini. Entomologica Scandinavica, 29, 89 98. http://dx.doi.org/10.1163/187631298x00212 Marvaldi, A.E. (2003) Key to larvae of the South American subfamilies of weevils (Coleoptera, Curculionoidea). Revista Chilena de Historia Natural, 76, 603 612. http://dx.doi.org/10.4067/s0716-078x2003000400005 IMMATURE STAGES OF LIXUS PUNCTIVENTRIS Zootaxa 3754 (2) 2014 Magnolia Press 171
May, B.M. (1993) Larvae of Curculionoidea (Insecta: Coleoptera): A systematic overview. Fauna of New Zealand, 28, 1 221. May, B.M. (1994) An introduction to the immature stages of Australian Curculionoidea. In: Zimmerman E.C. (Ed.), Australian weevils. Vol. II. Brentidae, Eurhynchidae, Apionidae and a chapter on immature stages by Brenda May. CSIRO, Melbourne, 755 pp. Mellini, E. (1950) Insetti del Carduus nutans L. I. Lixus elongatus Goeze. Bolletino dell' Instituto di Entomologia della R. Università degli Studi di Bologna, 18, 272 292. Nikulina, O.N. & Gültekin, L. (2011) Larval morphology of Lixus cardui Olivier and Lixus filiformis (Fabricius) (Coleoptera: Curculionidae): biological control agents for scotch and musk thistles. Australian Journal of Entomology, 50, 253 257. Nikulina, O.N. (2001) Larval morphology of the weevil genus Lixus (Coleoptera, Curculionidae) from Middle Asia. Entomological Review, 81, 809 823. [Original text published in Russian in Zoologicheskiy Zhurnal, 80 (10), 183 195.] Nikulina, O.N. (2007) New data on larvae of weevils of the genus Lixus (Coleoptera, Curculionidae) from Central Asia. Entomological Review, 87, 750 756. [Original text published in Russian in Zoologicheskiy Zhurnal, 86 (9), 1086 1092.] http://dx.doi.org/10.1134/s0013873807060103 Nikulina, O.N. (2008) Larval morphology of the weevil genus Ceutorhynchus (Coleoptera: Curculionidae) from Middle Asia. Entomological Review, 88, 867 873. [Original text published in Russian in Zoologicheskiy Zhurnal, 87 (10), 1274 1280.] http://dx.doi.org/10.1134/s0013873808070117 Nikulina, O.N., Guc, S. & Gültekin L. (2004) Larval morphology of the capitulum weevil, Larinus latus (Herbst) (Coleoptera, Curculionidae). New Zealand Journal of Zoology, 31, 23 26. http://dx.doi.org/10.1080/03014223.2004.9518355 Scherf, H. (1964) Die Entwicklungstadien der Mitteleuropäischen Curculioniden (Morphologie, Bionomie, Ökologie). Abhadlungen der Senckenbergischen Naturforschenden Gesellschaft, 506, 1 335. Skuhrovec, J. (2004) Descriptions of the larvae of the tribe Hyperini (Coleoptera: Curculionidae): I. Mature larvae of the nominotypical subgenus Hypera. Acta Societatis Zoologicae Bohemicae, 68, 245 280. Skuhrovec, J. (2006) Identification of instars of Hypera postica by using chaetotaxy. Journal of Economic Entomology, 99, 2216 2218. http://dx.doi.org/10.1603/0022-0493-99.6.2216 Skuhrovec, J. (2007) Descriptions of larvae of the tribe Hyperini (Coleoptera: Curculionidae): III. Mature larvae of the genus Donus Jekel, 1865. Zootaxa, 1606, 1 28. Skuhrovec, J., Gosik, R. & Caldara, R. (in press) Immatures of Palaearctic species of the weevil genus Tychius (Coleoptera, Curculionidae): new descriptions and new bionomic data with an evaluation of their potentiality in a phylogenetic reconstruction of the genus. Zootaxa. Ter-Minassian, M.E. (1936) Description of larvae of two Curculionid beetles living on Carduus uncinatus MB. Proceedings of the Zoological Institute of the Academy of Science of the USSR, 4, 173 178. [in Russian] Ter-Minassian, M.E. (1943) On the larvae of weevils of the genus Lixus F. (Coleoptera, Curculionidae). Izvestiya Armyanskogo Filiala Akaemii. Nauk SSSR, 1, 93 99. [in Russian] Wanat, M. (2011) Biology and distribution of Lixus punctiventris Boheman, 1835 (Coleoptera, Curculionidae) in Poland. Weevil News, 64, 1 5. 172 Zootaxa 3754 (2) 2014 Magnolia Press GOSIK & WANAT