Monolepta bioculata ( Fabricius, 1781 )

Wagner, Thomas, 2007, Monolepta Chevrolat, 1837, the most speciose galerucine taxon: redescription of the type species Monolepta bioculata (Fabricius, 1781) and key to related genera from (Chrysomelidae, Coleoptera), Journal of Natural History 41 (1 - 4), pp. 81-100 : 84-89

Redescription of Monolepta bioculata ( Fabricius, 1781)

Crioceris bioculata Fabricius, 1781, p. 154 .

Chrysomela quadrimaculata Goldfuss, 1805, p. 42 ; Gemminger & Harold (1876, p. 3593); Wilcox (1973, p. 533).

Monolepta bioculata ( Fabricius, 1781) : Chevrolat (1837, p. 407).

Monolepta tricolor Fairmaire, 1888, p. 222 ; Weise (1902, p. 404), Wilcox (1973, p. 533).

Total length. 4.8–6.2 mm (0: 5.50 mm; n 516).

Head. Red to reddish-yellow, palpi brown to black, maxillary palpi slender, labial palpi very short ( Figure 1a ). Distance of antennal grooves to each other much larger than distance to eye ( Figure 1b ). Second and third antennomere short, approximately of same length, in males short ( Figure 2a ) in females more elongated ( Figure 2b ), antennomeres 4–11 about 2.5 times longer than broad at apex ( Figure 3 ). Length of second to third antennomere 0.83–1.00 (0: 0.93), length of third to fourth antennomere 0.36–0.46 (0: 0.42). Antennomeres 1–3 yellowish-red to red ( Figure 8a ), sometimes also proximal half of fourth antennomere red ( Figure 8b ), other antennomeres dark brown to black ( Figure 8 ).

Thorax. Yellowish-red to red, pronotum broad, posteriorly slightly enlarged ( Figure 4a ). Pronotal width 1.80–2.10 mm (0: 1.94 mm), pronotal length to width 0.51–0.55 (0: 0.53). Prosternal processus posteriorly widened, prothoracic coxal cavities open ( Figure 4b ). Mesosternum slender, metasternum very broad ( Figure 5 ). Scutellum yellow to brownishred ( Figures 8 and 9 ). Basi-metatarsomere about two times longer than second and third tarsomere of metatarsus together ( Figure 6c ). Legs yellowish-red, in about 30% of material examined, tibia black. Hindwings fully developed, venation like Figure 7 . Elytra ovate, broad ( Figure 8 ); elytral length 4.10–4.70 mm (0: 4.43 mm), maximal width of both elytra 2.90–3.30 mm (0: 3.09 mm), maximal width of elytra to length of elytron 0.67–0.72 (mean: 0.70), greatest elytral width in the middle. Elytra yellow to brownish-red, each with two large yellow spots which usually have (in 70% of material examined) broad black margins which are incomplete at the basal spot ( Figure 8a ); in some specimens the black margins are very narrow ( Figure 8b ) but at least at the humerus with a significant black spot ( Figures 8 and 9 ).

Abdomen. Reddish-brown, rarely dark brown to black.

Female genitalia (overview Figure 10 ). Spermathecal cornu slender, slightly curved, middle part short, nodulus spherical, large ( Figure 11 ). Ventral part of bursa sclerites slender, finely undulate at outer margins ( Figure 12a ), dorsal pair triangular, hooked at base

( Figure 12b ), ovipositor with slender vaginal palps ( Figures 13 and 14 ), eighth sternite spatula-like with a row of bristles at apex ( Figures 13 and 15 ).

Male genitalia (overview Figure 16 ). Seventh sternite with two deep incisions at apex ( Figure 17 ). Median lobe straight, slightly conical, rounded at apex ( Figure 18a ), dorsoventrally compressed ( Figure 18b ). Tectum broad, short, not reaching the apex of the median lobe ( Figure 18a ). Endophallus with three distinct types of spiculae: ventral endophallic spiculae small, comb-like; median spiculae long, slender, straight; lateral spiculae slender, with claw-like small spine medially. During copulation the endophallic sac is extruded outside the median lobe and spiculae turned inside out ( Figure 19 ).

Figures

Figures 1–3. External morphology of Monolepta bioculata (Fabricius, 1781). (1) Head; a: ventral, showing mouthparts (ga: galea, lp: labial palpus, mdb: mandible, mp: maxillary palpus); b: dorsal (atg: antennal grooves, lbr: labrum). Scale bar: 1 mm (same for all following figures). (2) Basal antennal articles; a: two different males; b: two different females. (3) Antenna (left, female) showing hairs and bristles.

Figures 8–9. External morphology of Monolepta bioculata (Fabricius, 1781). (8) Dorsal colour patterns (white: yellow, dot-shaded: red, black: black). (9) Habitus.

Figures 4–5. External morphology of Monolepta bioculata (Fabricius, 1781). (4) Prothorax; a: dorsal; b: ventral (hm: hypomeron, pst: prosternum; pstpr: prosternal processus). (5) Meso- and metathorax, ventral view (msem: mesepimeron, msep: mesepisternum, msst: mesosternum, mtcx: metacoxa, mtem: metepimeron, mtep: metepisternum, mtst: metasternum).

Figures 6–7. External morphology of Monolepta bioculata (Fabricius, 1781). (6) Legs; a: prothoracic, b: mesothoracic, c: metathoracic. (7) Hindwing, left, dorsal view (A: analis, Cu: cubitus, M: media, R: radius, Sc: subcosta, rt: radial triangle, rm: cross vein).

Figures 10–12. Genital morphology of Monolepta bioculata (Fabricius, 1781), female. (10) Overview, from dorsal, tergites 1–7 removed (bc: bursa copulatrix, dbs: dorsal bursa slcerite, hg: hind gut, op: ovipositor, sp: spermatheca, spd: spermathecal duct, spg: spermathecal gland, st3–8: sternites, te8: 8th tergite, vbs: ventral bursa sclerite. (11) Spermatheca of three different females showing variation. (12) Bursa sclerites, view from inner side; a: ventral, b: dorsal.

Figures 13–15. Genital morphology of Monolepta bioculata (Fabricius, 1781), female. (13) Abdominal tip in lateral view (abbreviations see Figure 10). (14) Opivositor, view from inner side. (15) Eigths sternite, view from inner side.

Figures 16–17. Genital morphology of Monolepta bioculata (Fabricius, 1781), male. (16) Overview from dorsal, tergites 1–7 removed (ed: ductus ejaculatorius, hg. hind gut, ml: median lobe, spg: Spiculum gastrale, tc: tectum, te: tegmen, te8: 8th tergite). (17) Seventh sternite.

Figures 18–19. Genital morphology of Monolepta bioculata (Fabricius, 1781), male. (18) Median lobe, endophallus inverted, a: dorsal, b: lateral (with tegmen); lsp: lateral endophallic spiculae, msp: median endophallic spiculae, vsp: ventral endophallic spiculae. (19) Median lobe, endophallus partly extruded, a: dorsal, b: lateral (with tegmen); gp: gonoporus, further abrreviations see Figure 18.