Novius sexnotatus (Mulsant)

Poorani, J., 2023, A review of the tribe Noviini (Coleoptera: Coccinellidae) of the Indian subcontinent, Zootaxa 5311 (1), pp. 1-47 : 37-41

Novius sexnotatus (Mulsant)

( Figs 28–30 )

Epilachna sexnotata Mulsant, 1850: 807 .- Korschefsky 1931: 68 (as species incerta sedis).

Rodolia sexnotata: Booth & Pope 1989: 363 .

Novius sexnotatus: Pang et al. 2020: 20 .

Vedalia guerinii Crotch 1874: 282 .

Rodolia guerinii: Korschefsky, 1931: 101 .-Synonymised by Booth & Pope 1989: 363.

Rodolia immsi Weise, 1912: 120 .- Korschefsky 1931: 101; Kapur 1949: 535.

Diagnosis. Length: 4.80 mm; width: 3.80 mm. Form ( Fig. 28a–c , 29a–c ) broad oval to subovate, widest above middle of elytra, narrowed towards apex in posterior half, dorsum convex and densely pubescent. Ground colour bright carmine red or reddish brown. Pronotum with a pair of black spots on posterior margin, sometimes reduced or fused into a large transverse spot. Each elytron with three black spots, two below anterior margin, positioned above middle, sometimes fused to form a transverse macula, and one larger spot in the apical third. Abdominal postcoxal line complete, somewhat more deeply semicircular compared to other congeners ( Figs 28e , 29d, e ); posterior margin of abdominal ventrite 5 broadly emarginate and that of ventrite 6 apically weakly produced and broadly arcuate in female ( Fig. 29f ), ventrite 6 medially deeply emarginate in male ( Fig. 29d ). Male genitalia ( Figs 28f–h , 29g –i ) with penis guide of tegmen in inner view parallel-sided up to middle, narrowed thereafter, apical one–fifth more abruptly narrowed to a tubular apex ( Figs 28g , 29h ), apex obliquely arrow-head shaped in lateral view ( Figs 28f , 29g ); parameres distinctly longer than penis guide and apically narrowed, with short hairs on inner margin and apices; penis almost uniformly slender ( Figs 28h , 29i ), apically modified as illustrated ( Fig. 28i ). Female genitalia ( Fig. 29j ) as illustrated, spermatheca ( Fig. 29k ) almost globular without well differentiated nodulus and ramus, sperm duct distinctly broader than in other congeners.

Immature stages. Larva fleshy, fusiform, dull red to dark reddish brown ( Fig. 30a–h ). Pupa ( Fig. 30i ) reddish brown.

Material examined. INDIA: Tamil Nadu: Veerachipatti, Karur Dist. , iii.2022, feeding on Icerya pilosa on sugarcane, R. Thanigairaj, 10 ex. ( NRCB) .

Distribution. India (Karnataka, Madhya Pradesh, Uttarakhand, Uttar Pradesh, Tamil Nadu, Sikkim, Shivaliks); Pakistan; Bhutan; Nepal (Canepari 2003); Hong Kong (Rao & So 1967).

Prey/associated habitat. Icerya seychellarum (Westwood) , Icerya pilosa Green on sugarcane and wild grasses (label data). An important natural enemy of Drosicha stebbingii (Green) in sal ( Shorea robusta ) forests of north India ( Beeson 1941). All the specimens examined from South India (Tamil Nadu and Karnataka) were collected on sugarcane (label data).

Stebbing (1903, 1914) described the life stages and illustrated the adult with brief notes on its biology and his illustrations seem to match N. sexmaculatus more accurately than N. sexnotatus (see notes under N. sexmaculatus ). Beeson (1941) provided notes on its biology.

Venkatraman (1946) recorded it (as Rodolia guerini ) as a predator of all stages of the sugarcane scale, Icerya pilosa nardi Green (= Icerya pilosa Green ). He described the feeding behavior of the larvae as follows: “(…) the grubs rupture the dorsum of the nymphs with their large mandibles and feed on the body contents” and “in the case of older nymphs, as many as 3 to 4 grubs were found to attack a single specimen”.

Seasonal occurrence. Very active in April–May in north India. Collected during March–April (Tamil Nadu),

November (Karnataka).

Natural enemy. Venkatraman (1946) mentioned that ‘the grubs were heavily parasitized by Homalotylus flaminius (Dalman) ”, reducing their efficacy in controlling the sugarcane scale.

Notes. Novius sexnotatus was originally described from South India but appears to have a wide distribution in India and the specimens from South India are generally smaller than those from north and north-eastern India. The specimens from the north-eastern region appear to be slightly different but their genitalia could not be studied for confirmation.

Kapur (1949) erroneously synonymised N. sexmaculatus with N. guerini (see notes under N. sexmaculatus ). Variants of N. guerini with larger elytral maculae also resemble N. quadrimaculatus (Mader) var. 6-maculatus.

Figures

FIGURE 28. Novius sexnotatus (Mulsant): a. adult, dorsal view (BMNH); b, c. variant from Tamil Nadu; d. prosternal intercoxal process; e. abdominal postcoxal line; f–i. male genitalia: f. tegmen, lateral view; g. tegmen, inner view; h. penis; i. penis apex.

FIGURE 29. Novius sexnotatus (Mulsant): a–c. adult, dorsal view; d. abdomen, male; e. abdominal postcoxal line; f. apical ventrites, female; g–i. male genitalia: g. tegmen, lateral view; h. tegmen, inner view; i. penis; j. female genitalia; k. spermatheca.

FIGURE 30. Life stages of Novius sexnotatus (Mulsant): a–d. larva feeding on Icerya pilosa on sugarcane; e, moulting larva; f, g. full grown larva; h. mature larva feeding on Icerya pilosa; i. pupa; j. emerging adult; k, n. adult feeding on Icerya pilosa; l. teneral adult; m, o. adult beetle on sugarcane.