Liogma serraticornis, ALEXANDER, 1919

Imada, Yume, 2021, Moss mimesis par excellence: integrating previous and new data on the life history and larval ecomorphology of long-bodied craneflies (Diptera: Cylindrotomidae: Cylindrotominae), Zoological Journal of the Linnean Society 193, pp. 1156-1204 : 1183

LIOGMA SERRATICORNIS ALEXANDER, 1919

( FIGS 5F , 6F , 16E–I )

Life history: This species is univoltine; adults emerge during May–July, in central Japan. Larvae occur on moss tufts of Mniaceae in relatively wet spots in the forest or woodland. The matured larvae often are found lying underneath thalli of thallose liverworts, especially Conocephalum conicum (L.) Dum. ( Conocephalaceae ), or amongst shed old pine needles of Cryptomeria japonica (Thunb. ex Lf.) Don ( Pinales : Cupressaceae ) into which individuals with dark brown hue blend well.

Final-instar larva: Length 20 mm (N = 10). Body colour various with light green ( Fig. 16E ) or dark brown hue ( Fig. 16F ). Dorsal pigmentation pattern well organized: prothorax lacks pigmentation; meso- and metathorax nearly entirely pigmented; in abdominal segments I–VII, dark blotches appear as inverted Y-shape, broadly diffused anteriorly ( Fig. 16G ); in some individuals, small blotches also occur ventrally. Integument translucent, except for pigmented parts, surface rugulose ( Fig. 6F ). Prothorax dorsally with six lobes along pronotal ridge having blunt apices; middle two longer and conical, outer two shorter and tuberculate ( Fig. 16H ). Meso- and metathorax with two pairs of dorsal lobes, both bearing two button-shaped auxiliary outgrowths at the front; two pairs of lateral lobes, anterior pair larger; two pairs of ventral lobes. Dorsal lobes on abdominal segments slender and each pair clinging to each other with bluntly pointed apices ( Fig. 6F ): segment I with three pairs, posteriormost pair carrying two auxiliary outgrowths; segments II–VII with four pairs, posterior two pairs bearing two auxiliary outgrowths ( Fig. 6F ). Lateral lobes on abdominal segments relatively long, apices obtuse and bent backwards; segments I and II–VII with three and four pairs, respectively. Ventral lobes on abdominal segments relatively long, apices significantly oriented backwards. Anal segment with one pair of dorsal lobes; dorsomedial lobe absent; two pairs of ventral lobes, anterior pair papilla-like (black arrowheads, Fig. 16I ); four anal papillae (anp) present ( Fig. 16I ). Spiracular field with hair fringe.

Host-plants: The larvae feed on several moss species belonging to Mniaceae (Bryales) , including Mnium lycopodioides (Hook.) Schwägr. , Plagiomnium maximoviczii , Pl. tezukae (Sakurai) T.J.Kop. , Pl. vesicatum , Rhizomnium hattorii and R. tuomikoskii T.J.Kop.

Figures

Figure 5. Schematic diagram illustrating diverse arrangements and numbers of the elongated cuticular lobes in 11 cylindrotomine species. Each diagram represents a simplified larval body, longitudinally grouped into six, based on the patterned arrangements of the lobes: (1) prothorax, (2) meso- and metathorax, (3) abdominal segment I, (4) abdominal segment II, (5) abdominal segments III–VII, and (6) abdominal segment VIII (anal segment). Each square partitioned by double lines in a row denotes the integument on the dorsal (dl), lateral (la), ventral (vl) sides of the corresponding segment(s). Each black dot symbolizes a cuticular lobe, of which position/size in a given space express the relative position/size of the lobe.Anal papillae are not shown. Lobe forms, auxiliary outgrowths, and relative length of segments are not shown here (see each species' own description). Each taxon name is abbreviated. For G and I, diagrams are based on the description in Brodo (1967) and Peus (1952), respectively; caution is needed when these are compared with the species examined herein (A–F, I–K), because the lobe characteristics could be treated differently in the previous studies. For K, a single lobe is present at the location of asterisk (*) only in the abdominal segment VII but not in the other segments.

Figure 6. Comparative morphology of dorsal elongated cuticular appendages on abdominal segment in cylindrotomine larvae at late instar. (A) Cylindrotoma japonica. (B) Diogma glabrata. (C) Liogma brevipecten. (D) L. mikado. (E) L. nodicornis. (F) L. serraticornis. (G) Triogma kuwanai. (H) Phalacrocera replicata. For C, E and H, body colour is faded away due to preservation in alcohol. Scale = 1 mm.

Figure 16. Biology and morphology of Liogma mikado, L. nodicornis, L. serraticornis. (A–C) L. mikado. (A) Late-instar larva, lateral view. (B) First-instar larva (scale = 0.5 mm). (C) Early-instar larva on a tuft of Plagiothecium euryphyllum (Plagiotheciaceae). (D) Late-instar larva of L. nodicornis, feeding on Plagiomnium ciliare (Mniaceae). (E–I) L. serraticornis. (E) Late-instar larvae with green hue, feeding on Plagiomnium vesicatum (Mniaceae). (F) Late-instar larvae with brown hue feeding on Mnium lycopodioides (Mniaceae), found in the same population as the individual shown in (B). (G) Habitus of lateinstar, dorsal view; mesoand metathoracic segments are entirely dark and inverted Y-shaped pattern is evident in abdominal segments I–VII. (H) Characters of head. (I) Characters of anal segment. Black arrows indicate papilla-like, anterior pair of the ventral lobes. Abbreviations: anp, anal papilla; dl, dorsal lobe; pr, pronotal ridge; vl, ventral lobe. Scale (except B) = 1 mm.