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Setora Walker
Type species: nitens Walker
This is a large and complex genus containing numerous rather similar bronzy
brown species with its centre of diversity in mainland Asia but extending as far
east as Sulawesi. The species are serious pests of a variety of crops and will
be treated in more detail in Cock, Godfray & Holloway (in press). The name Setora
nitens as used in the economic literature embraces a complex of half a dozen
or more species, two of which occur in Borneo with a third more distinctive one (tamsi
Hering).
The forewing facies has elements in common with Praesetora and Birthamoides
in that a more or less oblique, but in this case curved post- medial
converges at the costa with a submarginal; the submarginal is usually diffuse,
reflective, and often obscure. In many species there is a triangular zone of
paler brown subapically on the costa
The antennae are broadly bipectinate to one third and the palps typical
of the crescent-signum group. Most species have a white patch at the apex of the
foretibia though S. tamsi is an exception.
The male genitalia are typical of the ground plan except the valves when
spread on a slide are more acutely angled to the vertical axis by 30° rather than between 60° and at right angles to it. The furca arms are
out-curved, sabre-like. The aedeagus usually has a group of very small spines
just subapically.
The female genitalia are typical of the crescent-signum group, the
ductus bursae being sclerotised basal to the ductus seminalis in the two Bornean
members of the nitens complex but not in some mainland Asian taxa or
those from Sulawesi and the Philippines. The tergite of the eighth segment is
distally scobinate in most species, and in the Bornean species of the nitens complex
it is produced in two lateral lobes that overlap the ovipositor lobes.
The larvae of nitens group species are parallel sided, deeper
than broad, with the row of laterals complete, small to very small alternately.
Of the subdorsals those of T2 are small, T3 large, Al and A5 moderate, and A8
large. Both the large pairs have the spines black banded, the laterals on T3 are
similar and the small ones on T2 also invested with black. The rest are as the
ground colour. The larva is usually green with a dorsal band that is mainly blue
and lateral row of oblique reddish brown oval marks between the tubercle
positions above the laterals. The ground colour can be yellow-green or shades of
red (Piepers & Snellen 1900).
A wide range of host-plants has been recorded for the complex (Piepers
& Snellen 1900; Wood 1968; Kalshoven 1981; unpublished CIE records): Musa
(Musaceae); Elaeis, Cocos (Palmae); Theobroma (Sterculiaceae);
Coffea, Cinchona (Rubiaceae); Nephelium (Sapindaceae); Camellia
(tea, Theaceae); Citrus (Rutaceae); Pittosporum (Pittosporaceae);
Nicotiana (Solanaceae); Elettaria (Zingiberaceae).
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