Conicofrontia diamesa ( Hampson, 1920 )

Ru, Bruno Le, Capdevielle-Dulac, Claire, Conlong, Desmond, Pallangyo, Beatrice, Berg, Johnnie Van Den, Ong’Amo, George & Kergoat, Gael J., 2015, A revision of the genus Conicofrontia Hampson (Lepidoptera, Noctuidae, Apameini, Sesamiina), with description of a new species: new insights from morphological, ecological and molecular data, Zootaxa 3925 (1) : -

Conicofrontia diamesa ( Hampson, 1920)

( Figs. 1 e–1h, 3b, 3f, 3j, 4b)

Arenostola diamesa Hampson, 1920: 257 .

Conicofrontia diamesa (Hampson) : Tams & Bowden, 1953:652.

Material examined. Holotype (male) of Arenostola diamesa : Republic of South Africa: Zululand, Eshowe, xii 1916, Agrotidae genitalia slide 1292, E.E. Platt Coll. [ BMNH].

Other material: Republic of South Africa: 3♂, 4♀, Eston, 29°55.102’S, 30°37.222’E, 673m a.s.l., 02.ii.2009, ex larva (in stem of Cymbopogon sp.) [2♂ gen. prep LERU Bruno/G300-G643, 2♀ gen. prep LERU Bruno/G55-G301] (B. Le Ru, leg.) [ MNHN].

Redescription. The male holotype was poorly described by Hampson (1920). The male looks very similar to the female, however the general shape of the female’s forewing is more elongated at the apex. Additions to the previous descriptions ( Figs. 1 e–1h): antennae ochreous, filiform in female, serrate in male, cilia short, fasciculate, flagellum adorned dorsally with brown scales, palpus brown, eyes red brown. Head and front of thorax ochreous brown, tegulae bisque, legs brown ringed with bisque, abdomen brown ochreous, anal tuft ochreous. Forewing: a longitudinal brown fascia suffused with fuscous scales from the base along the lower margin of the cell partly within the cell, partly without, extending to just before the termen; the cell, costa, apex, termen and inner margin bisque with areas between veins suffused with fuscous scales in apex and termen; 2–3 small black spots along the upper margin of the cell, sometimes one additional black spot in front of the cell. Fringe bright ochreous or bisque adorned successively from the base with a narrow basal brown line, a thick bisque line and a thick brown line. Hindwing; grey bistre strongly suffused with brown scales; fringe bistre with a narrow grey bistre line at the base. Underside of the forewing bistre suffused with brown and fuscous scales on the costa and apex, strongly suffused with brown scales from the cell to the termen, less suffusion in the inner margin. Underside of hindwing grey uniformly suffused with brown and fuscous scales but more densely on costa and apex; veins of both forewing and hindwing adorned with fuscous scales.

Wingspan 24–27 mm (males) (n = 6); 26–28 mm (females) (n = 6).

Male (27, 26, 25, 25, 24, 26), Female (27, 28, 26, 26, 27, 27)

Male genitalia ( Figs. 3 b, 3f). Uncus long and wide, tapering to a fine point and tufted with long hair on the upperside; tegumen with medium-size rounded peniculi, vinculum with medium-size triangular saccus; valves elongate and narrow, cucullus elongate, rounded at apex and tufted with medium size hairs; sacculus with an heavily sclerotized and dentate clavus, dents larger at both ends; the presence of a sclerotized and heavily dentate plate across the upper edge of the sacculus, costal margin with a small sclerotized ridge-like expansion roundly pointed and slightly curved inwardly; the juxta plate like, short and becoming smaller towards the top. Aedeagus short, slightly curved, manica with a two-lobed sclerotization, less than one fifth length of the aedeagus, ending in a spinose tip; vesica with two strongly dentate ventral cornuti, almost one third length of the aedeagus.

Female genitalia ( Fig. 3 j). Corpus bursae long and cylindrical with one signa; ductus seminalis from the basal part of the bursa; ductus bursae broad and strongly sclerotized on the ostium side; ventral plate of ostium bursae sclerotized bilobate deeply invaginated at middle, thus forming a circular-shaped ventral wall of antrum; dorsal plate large, broad, weakly sclerotized. Ovipositor lobes short and wide (1.5 times longer than wide) with many stout bristles in addition to the small setae and an apical crest of short stout bristles.

Larvae L5 instar ( Fig. 4 b): length, 30–35mm, width, 3.5 mm; head smooth, orange brown, prothoracic shield yellow orange; body with ground colour buff, dorsally suffused with pink, pinacula pale yellow and caudal plate brown. Young larvae are very similar in appearance to mature ones.

Bionomics. Conicofrontia diamesa is a hygrophilous species inhabiting grasses along banks of streams, rivers and marshes. Larvae were collected at the bottom of young stems of Cymbopogon sp. stems, always solitary. Typically, plants exhibiting signs of infestation by C. diamesa larvae have a curled, brown, central leaf. Damaged stems had a small hole (ca. 2 mm diameter) located approximately 10 cm from ground level. We suspect that the larvae disperse when they reach the fourth instar. No pupae were found in stems, and therefore borers probably pupate in the soil.

Distribution. South Africa. The two records are from Afromontane (Mosaic no 19) vegetation mosaic ( White 1983) ( Fig. 6 ).

Remarks. Easily separated from other Conicofrontia species with the short juxta plate-like, the dentate clavus with dents larger at both ends, the two strong dentate ventral cornuti of the vesica and the ventral plate of ostium bursae, sclerotized bilobate, deeply invaginated at middle, thus forming a circular-shaped ventral wall of antrum.

Figures

FIGURE 1. Adults of Conicofrontia species (C. bipartita and C. diamesa). Scale bar = 10 mm.

FIGURE 3. Genitalia of Conicofrontia species. Scale bar = scale bar = 1 mm and 0.5 mm for male penis. Conicofrontia bipartita: 3 a—male genitalia, 3 e—male penis, 3 i—female genitalia.

FIGURE 4. Last instar larvae of Conicofrontia species. Scale bar = 10 mm.

FIGURE 6. Distribution map of sampled Conicofrontia and Hygrostola specimens.