Agonosoma trilineatum ( FABRICIUS 1781 )

Gerry Cassis & Loren Vanags, 2006, Jewel Bugs of Australia (Insecta, Heteroptera, Scutelleridae), Denisia 19, pp. 275-398 : 330-332

Agonosoma trilineatum ( FABRICIUS 1781) ( Figs 16 , 17 , 18 , Table 6 )

Cimex trilineatus FABRICIUS 1781: 341 (n. sp.) Cimex sexpunctatus FABRICIUS 1781: 339 (n.sp.); PALEARI 1992: 513 (synonymy) Cimex trivittatus PANZER 1798: 111 (n.sp.); PALEARI 1992: 513 (synonymy) Pachycoris virgatus GERMAR 1839: 102 (n.sp.); PALEARI 1992: 513 (synonymy) Agonosoma quadiguttatum SIGNORET 1851: 330 (n.sp.); WALKER 1867: 59 (list); PALEARI 1992: 513 (synonymy) Agonosoma trivittatum : SIGNORET 1851: 330 (new combination); DALLAS 1851: 42 (list) Agonosoma trilineatum : STÅL 1870: 13 (new combination); SCHOUTEDEN 1904: 68 (synonymy); PALEARI 1992: 505 (redescription) Agonosoma trivittata fabricii KIRKALDY 1909: 278 (unnecessary nom. nov.)

Diagnosis: Agonosoma trilineatum is recognised by the following combination of characters: males chocolate brown, with three longitudinal yellow stripes ( Fig. 16a ); females dimorphic, as in male, or mostly yellow-brown, with pair of submedial spots on pronotum and scutellum ( Fig. 16b ).

Colouration. Males monomorphic, dorsum dark chocolate brown with three longitudinal yellow stripes ( Fig. 16a ); females dimorphic, either as in male, or pale brown with black spots ( Fig. 16b ). Head: jugal margins black, subjugal regions of frons orange, large fuscous triangular marking from posterior margin of head to near anteclypeus, with medial yellow stripe; underside of head mostly iridescent green, with posterior region orange; AI orange, sometimes tip embrowned, remainder of segment fuscous; LIII mostly dusty stramineous, LIII-LIV fuscous; Pronotum: spotted morph with 6 spots, pairs on anterolateral angles, submedially on anterior margin, and submedially below callosite region. Thoracic pleura: anterior edge of proepisternum yellow, remain-der of pleura fuscous, with green iridescent tinge, intermixed with yellow posterior margin of mesepimeron and peritreme and part of supracoxal lobes. Legs: coxae yellow; femora orange; tibiae fuscous in stripped morph, or mostly orange with anterior surface fuscous; tarsi fuscous. Abdominal Venter: ground colour yellow-orange, with lateral margins dark brown and green iridescence, SV-SVI stridulatory vittae dark brown, SII mostly dark brown, anterior margins of SIII-VII dark brown.

Texture. Dorsum, underside of head and thoracic pleura punctate ( Figs 16a, b , 17b ).

Vestiture. Body glabrous. Antennae: AI-AII(a) almost glabrous, AII(b)-AIV with dense distribution of short, simple, semi-erect setae; femora with sparse distribution of short setae; ventral surface of tibiae with dense distribution of short, semi-erect setae.

Structure. Antennae: AII(a) smallest segment, AIV longest segment,> AIII, AII(b) little longer than AII(a), AII(b) subequal to AI; AIII and AIV flattened. Labium: reaching abdominal SIII, LII longest segment. Male Genitalia: pygophore with narrow genital opening, laterally setose ( Fig. 17d , 18a ); parameres with short, broad stem and angulate, elongate crown ( Fig. 18b ); aedeagus with sclerotized, broad ductus seminis proximalis, bounded by ligamentory tubule ( Fig. 18c ); ejaculatory apparatus with ventral conducting canal broad, not convoluted ( Fig. 18c ); ejaculatory reservoir elongate, subreniform ( Fig. 18c ); ductus seminis distalis broad, scerlotized ( Fig. 18c, d ); vesica membraneous, denticulate ( Fig. 18c, d ); CAI and CAIII absent ( Fig. 18c ); CAII broad, antler-like, distally denticulate ( Fig. 18c ). Female Terminalia: paratergites VIII small, subtriangular, tapered medially; paratergites IX large, subelliptoid, medial margins rounded; gonocoxae I bipartite, posterior, digitiform branch, anteriorly sub-triangular, moderately-sized. Spermatheca: fecundation canal short; reservoir very weakly dilated, thickened; pump elongate, with proximal and distal flanges present; bulb small, round.

Measurements. Table 6 .

Material examined: Venezuela: 5♂♂ 11♀♀, Falcon State, Paraguana Peninsula , 15 December 1999, R Segura & TA Heard, ex Jatropha gossypifolia , quarantine colony ( AM).

Distribution: This species was intro-duced to southeast Queensland, and natu-ralised populations are as yet to be recovered (Heard pers. comm.). It is naturally known from Panama, Colombia, Venezuela, Suri-nam, Grenada and Trinidad ( PALEARI 1992).

Host plants and biology: Agonosoma tri-lineatum was introduced as a biocontrol agent of Jatropha gossypifolia (see above).

Remarks: PALEARI (1992) redescribed this species, highlighting the colour dimor-phism, external morphology and distribu-tion. It is distinguished from all the native jewel bugs of Australia, on colour and colour patterning alone. It is easily diag-nosed by the enlarged abdominal SVII of both sexes (covering the terminalia) ( Fig. 17d , male), the membraneous vesica (Figs 18c, d), and thickened and narrow sper-mathecal reservoir.

Figures

Fig. 16: Habitus of introduced Pachycorinae species (a-b) Agonosoma trilineatum (a) ♂ (b) ♀. Scale bar = 1 mm.

Fig. 17: Scanning electron micrographs of key characters of Agonosoma trilineatum (a) Head, dorsal view (b) Head, lateral view (c) External efferent system of metathoracic glands, ventral view (d) male pygophore, dorsal view (e) Stridulatory areas, pregenital abdominal SV- SVI (f) Substructure of stridulatory area. Abbreviations: Ea = evaporative area; Pe = peritreme; P(r) = right paramere; S = stridulatory area; SVII = seventh abdominal sternite, dorsal view. Scale bars = 0.1 mm.

Fig. 18: Male genitalia of Agonosoma trilineatum (a) pygophore, dorsal view (b) paramere, lateral view (c) aedeagus, lateral view (d) apex of aedeagus, ventral view. Abbreviations: C = crown of right paramere; DS(D) = ductus seminis distalis; DS(P) = ductus seminis proximalis; Er = ejaculatory reservoir; F = flange at base of crown of paramere; GO = genital opening; Pt = phallotheca; S = stem of paramere; Sg = secondary gonopore; V = vesica; VM = ventral margin of genital opening.