Bolitophagus reticulatus

Wagner, Grzegorz K. & Gosik, Rafał, 2016, Comparative morphology of immature stages of two sympatric Tenebrionidae species, with comments on their biology, Zootaxa 4111 (3), pp. 201-222 : 203-211

Description of mature larva and pupa of Bolitophagus reticulatus

Mature larva. Coloration ( Figs. 6–8 ). Head brown, thoracic and abdominal segments I–VI dark yellow to brown, remaining segments brown to dark brown; anal lobes dark brown; legs yellowish to brown. Thoracic and abdominal tergites more pigmented than remaining parts of the body. Cuticle densely, covered by fine asperities.

Body shape and chaetotaxy ( Fig. 14 ). Body: length 9.5–12.5 mm, greatest width (at metathorax or abdominal segment I) 1.3–1.5 mm, shape moderately elongated, rounded in cross section, slightly curved. Chaetotaxy well developed, setae various in length, transparent or yellowish, always hair-like. Thorax: Prothorax almost as long as wide; both meso- and metathorax approximately 1.5 times broader than long. Prothorax with a row of long and medium long setae situated close to anterior margin; meso- and metathorax each with similar groups of setae situated dorso-medially; each of thoracic segments with groups of several setae of various length placed laterally. Legs ( Figs. 16, 17 ): forelegs longer and more massive than next pairs (especially coxae of forelegs distinctly stout); trochanter short, conical, femur of foreleg conical, of mid- and hindlegs subcylindrical, tibiotarsus elongated, all covered irregularly with number of setae; claws elongated dark brown, with a seta placed ventrally; claws almost two times shorter than tibiotarsus. Abdomen: Abdominal segments I – IV almost of equal length, next abdominal segments decreasing gradually to the terminal parts of the body. Abdominal segment X reduced to four anal lobes of almost equal size. Anus located terminally. Tergites of segments I–VII with two rows of setae (first located along anterior margin, second situated medially). Long and short setae placed in both rows alternatively. Abdominal segments I–VII with a group of several, various in length setae placed laterally. Medial parts of abdominal segments I–VII with 4 – 6 equal in length setae. Setae of abdominal segment VIII well developed. Dorsal and lateral parts of abdominal segment IX densely covered by numerous setae of various length. Abdominal segment IX with a pair of small, conical urogomphi, strongly sclerotized, localized dorso-laterally, slightly curved to inside. Urogomphi and anal lobes without setae ( Fig. 15 ).

Head ( Fig. 18 ), width 1.3–1.55 mm, hypognathous, almost oval, sutura coronalis weakly visible, sutura frontalis not reaching antenna, frons relatively small, triangular. Epicranium and frons covered by numerous hairlike setae of various length. Setae do not form any regular pattern. Antennae ( Fig. 19 ) trimerous; antennomere I distinctly wider than long; antennomere II 1.7 times as long as wide, slightly narrowed in apical part, with 4 setae; antennomere III slender, finger-like, with one seta and two sensillae apically (one of them with a seta situated on the top). Basalpart of antennomere II more pigmented than the upper part, so whole antennomere seems to consist of two rings. Clypeus (Fig. 20—left side) convex in lateral view, transverse, trapezoidal, anterior margin strongly hollowed. Basal part of clypeus more pigmented then middle and distal parts. A pair of long setae located mediolateral on each side. Labrum (Fig. 20) almost as long as wide, with rounded anterior margin its dorsal surface flat in lateral view, with eight long and four short setae. All setae placed more or less marginally. Epipharynx (Fig. 20—right side) with four short marginal setae; two of them placed apically, next laterally. Mandibles ( Figs 21 a – b) asymmetrical, strong sclerotized, bifid, in dorsal view with three long setae, placed laterally; right mandible wide, with well developed, semicircular molar part and small triangular tooth close to apical part; left mandible narrow, with short cut molar part and triangular tooth located basally. Each of mandibles bears dorso-laterally distinct conical process with oblate apex. Maxilla ( Fig. 22 ): stipes bears eight setae various in length, palpus threesegmented, both segments I and II almost as long as wide, with two and three setae respectively, segment III longer than wide, sub-conical, with some sensillae apically. Lacinia densely covered by numerous thick, various in length, curved setae. Labium ( Fig. 22 ) divided into prementum, mentum and submentum. Prementum almost oval-shaped, with a pair of setae placed antero-laterally; mentum subcylindrical, tapering in apical part, with three pairs of setae equal in length, located medio-laterally; submentum centrally, almost two times wider than longer, with a pair of long setae medially; ligula concave with two pairs of short, thick setae placed apically. Labial palpi two-segmented.

Pupa. Coloration ( Figs 9 – 11 ). Body yellowish to greyish (changing its color during preservation into brown), claws dark brown, lateral processes more pigmented yellow with brown spines.

Shape, chaetotaxy and lateral processes. Body ( Figs 23 – 25 ) rather elongated, slightly curved, oblate dorsoventrally, length: 5.5–7.7 mm, width (measured on the level of second pair of legs): 3.0–4.0 mm, chaetotaxy developed, setae hair-like, straight, yellow, various in length. Gin traps of abdominal tergites I – VI well developed ( Figs 12, 13 , 26 ); on the first abdominal segment, triangular, bear apical spine and some very fine setae; on abdominal segments II – VI conical, divided apically, consist of anterior spine, lateral spine and massive posterior spine; anterior borders possess 4 – 6 various in size triangular teeth; posterior borders with 2 – 3 long spines and two hair sensillae. Abdominal segments I – VII decreasing gradually, segment VII conical, IX strongly reduced. Tergite IX with a pair of elongated slightly curved to inside urogomphi, with sclerotized apical parts. Head ( Fig. 27 ) wide, eyes well visible, black; marginal parts of head irregular covered by numerous short setae; medial part ridged, without setae, clypeus transversely wrinkled, with single setae on each side; labrum trapezium-shaped with seven setae along its anterior margin. Pronotum ( Fig. 31 ) transversely wrinkled with serrated, dark sclerotized lateral parts; lateral angles elongated, central part of pronotum regular, covered by numerous short setae, borders bear distinctly longer setae; hypomeron glabrous; elytral and metathoracic wing sheaths smooth, mesonotum slightly shorter than metanotum, both almost as long as first abdominal tergum; each of them with a horizontal row of setae medially. Spiracles seven pairs, first elongated, placed between pro- and mesonotum, next six pairs rounded, located medio-laterally on abdominal segments I – VI. Abdominal tergites I – VI ( Fig. 32 ) with rows of weakly visible short setae, situated medially, tergite VII ( Fig. 33 ) with numerous of various in length setae located medially and postero-medially; tergite IX ( Fig. 34 ) covered by numerous elongated setae; abdominal ventrites I – VIII ( Fig 28 ) with weakly visible, short setae, distributed medially, ventrite IX with some elongated setae laterally. Gonotheca ( Figs 29 – 30 ) of female divided, elongated, covered by elongated setae; gonotheca of male undivided with groups of very long setae. Urogomphi without setae. Femora ( Fig. 35 ) bear several elongated setae; remaining parts of legs without setae.

Figures

FIGURES 6 – 13. Bolitophagus reticulatus, immature stages: 6 – 8 mature larva: 6 — lateral view, 7 — dorsal view, 8 — ventral view; 9 – 13 pupa: 9 — ventral view, 10 — lateral view, 11 — dorsal view, 12, 13 — lateral processes of abdomen (gin traps).

FIGURES 14 – 17. Bolitophagus reticulatus, mature larva, habitus and selected body parts: 14 — habitus and chaetoaxy, dorsal view (left side), ventral view (right side), 15 — abdominal segments 8 – 9 th (lateral view), 16 — front leg, 17 — mid leg (Th n — thoracic segment, Ab n — abdominal segment, ur—urogomphi, co—coxa, tr—trochanter, fe—femur, tt—tibiotarsus, cl—claw).

FIGURES 18 – 19. Bolitophagus reticulatus, mature larva, head and antenna: 18 — head shape and chaetotaxy: dorsal aspect (left side), ventral aspect (right side), 19 — right antenna, (at—antenna, cl—clypeus, lbr—labrum, md—mandible, ma—maxilla, lbm—labial complex, atn n — antennomere).

FIGURES 21 – 22. Bolitophagus reticulatus, mature larva, mouth parts: 20 — clypeus and labrum (left side), epipharynx (right side), 21 a—right mandible, 21 b—left mandible, 22 — maxillo-labial complex (cl—clypeus, lbr—labrum, epx—epipharynx, mpa n — maxillary palpomerae, stp—stipes, pmt—praementum, mt—mentum, smt—submentum, lac—lacinia, cls — clypeal setae, epxs — setae of epipharynx, lbrs — labral setae, lgs — ligular setae, pmts — praemental setae, mds — mandibular setae, mts — mental setae, smts — submental setae, stps — stipal setae).

FIGURES 23 – 26. Bolitophagus reticulatus, pupa, habitus and part of gin trap: 23 — total, ventral view, 24 — total (dorsal view), 25 — total (lateral view), 26 — lateral structure of third abdominal segment (Th n — thoracic segment, Ab n — abdominal segment, ur—urogomphi, atb—anterior border, pb—posterior border, hs—hair sensilla, as—anterior spine, ls—lateral spine, ps—posterior spine).

FIGURES 27 – 35. Bolitophagus reticulatus, pupa, chaetotaxy of selected body parts and sexual dimorphism: 27 — chaetotaxy of head, 28 — detail of Ab 8 (ventral aspect), 29 — ventral part of Ab 8 – 9 (female), 30 — ventral part of Ab 8 – 9 (male), 31 — detail of Th 1 – 3 (dorsal view), 32 — detail od Ab 1 (dorsal aspect), 33 — detail of Ab 7 (dorsal view), 34 — detail of Ab 8 – 9 (dorsal view), 35 — chaetotaxy of front and mid leg (ur—urogomphi, Thn—thoracic segment, Abn—abdominal segment, go—gonotheca, fes — femoral setae).