Scymnus (Pullus) rajeshwariae Poorani

Poorani, J., 2015, Two new species of Scymnini (Coleoptera: Coccinellidae) from Karnataka, India, Biodiversity Data Journal 3, pp. 5296-5296 : 5296

Scymnus (Pullus) rajeshwariae Poorani sp. n.

Materials

Type status: Holotype. Occurrence: sex: male; preparations: whole animal; Location: continent: Asia; country: India; stateProvince: Karnataka; municipality: Bangalore; locality: Hebbal ; verbatimCoordinates: 13°01'N, 77°35'E; Event: eventDate: 2002-01-01; eventRemarks: Feeding on Pseudoregmabambusicola on bamboo Type status: Paratype. Occurrence: sex: 7 males, 8 females; preparations: whole animal; Location: continent: Asia; country: India; stateProvince: Karnataka; municipality: Bangalore; locality: Hebbal ; verbatimCoordinates: 13°01'N, 77°35'E; Event: eventDate: 2002-01-01; eventRemarks: Feeding on Pseudoregmabambusicola on bamboo

Description

Length: 2.50-2.90 mm; Width: 1.70-2.10 mm; TL/TW: 1.33-1.40; PL/PW: 0.52-0.58; EL/EW: 0.97-1.05; EW/PW: 1.34-1.43. Male: Body outline (Fig. 1e) elongate oval, broadest around middle of elytra, elytra apically somewhat broadly rounded to subtruncate; dorsum densely pubescent with silvery white hairs. Head dark pitchy brown to black, anterior clypeal margin slightly lighter; pronotum black except anterior and lateral margins narrowly reddish testaceous; elytra black, apical one-fourth reddish brown-testaceous. Ventral side with mouthparts, legs and abdominal ventrites dark brown to testaceous, middle of abdominal ventrite 1 and remaining areas dark pitchy brown. Head with interocular distance about 1.7x as wide as an eye; punctures dense in posterior half, slightly more widely spaced towards clypeal margin, separated by <0.5-1 diameter. Antenna 11-segmented with a distinct club. Pronotum with punctures on disc shallow, separated by 1-4 diameters, denser and more closely spaced on lateral sides, separated by <1-2 diameters. Elytra with shallowly impressed punctures, slightly larger and denser than that on pronotum, separated by 1-2 diameters on disc, slightly coarser, denser and more closely spaced around anterolateral margins, interspaces between punctures coriaceous; with a row of slightly larger punctures on either side of suture in anterior half. Prosternal process (Fig. 2a) with a pair of apically divergent carinae. Abdominal postcoxal lines (Fig. 2c) complete, broadly semicircular to boat-shaped, area enclosed densely punctate in anterior half, punctures coarser and fewer in posterior half, apical one-fourth adjacent to postcoxal line more or less smooth, devoid of punctures. Ventrite 5 with posterior margin weakly emarginate, ventrite 6 truncate. Tarsi pseudotrimerous. Tarsal claws bifid with a basal tooth (Fig. 2b). Male genitalia (Fig. 2d, e, f) with penis guide lanceolate in ventral view (Fig. 2e), parameres shorter than penis guide in lateral view (Fig. 2d), bilobate with triangular / subconical inner expansions in anterior half, inner expansion much shorter than outer, with long apical hairs reaching beyond apex of outer lobe, apices of outer lobes of parameres with much longer, denser hairs reaching beyond apex of penis guide. Penis (Fig. 2f) coiled with a prominent capsule having a distinctly longer outer arm than inner arm, penis ---apex membranous with a short, hook-like projection.

Female: Similar to male. Tarsal claws (Fig. 2b) with a more transverse basal tooth than in male, anterior process distinctly shorter than posterior (in male basal tooth more distinctly quadrate, posterior process only slightly longer than anterior). Last abdominal ventrites not showing any marked dimorphism, ventrite 5 with posterior margin broadly arcuate, ventrite 6 subtruncate. Female genitalia (Fig. 1f) with spermatheca having well differentiated cornu, nodulus and ramus and a sclerotised rod-like projection on bursa.

Diagnosis

Scores of Oriental species of Scymnini are externally similar to S. (P.) rajeshwariae sp. n. in having black elytra with reddish brown / testaceous apices and are difficult to identify without examination of male genitalia. But the habits and male genitalia of this species appear to be unique. The male genitalia are very distinctive with bilobed parameres and the penis guide is apically lanceolate.

Etymology

This species is named for Ms. S.K. Rajeshwari, Technical Officer, NBAIR, who has been a great help and support in my work on Coccinellidae .

Distribution

India: Karnataka.

Biology

It appears to be a highly specific predator of the bamboo woolly aphid, Pseudoregma bambusicola (Takahashi) and is collected always in association with this species only. The larvae are greyish with white waxy dusting and lack the usual dense waxy filaments in many other Scymnus spp. (Fig. 1a, b, c). The larvae are commonly seen in aphid colonies on bamboo stem, but the adults are more cryptic in their habits and found feeding only under the leaf sheaths. There are several common predators of P. bambusicola which occur along with this species. These include the giant bamboo ladybirds, Synonycha grandis (Thunberg) and Megalocaria dilatata (F.) ( Coccinellidae ), Dipha aphidivora (Meyrick) ( Lepidoptera : Pyralidae ), and Dideopsis aegrota (F.) ( Diptera : Syrphidae ). In view of its specificity, this species could be a potential biological control agent of P. bambusicola on bamboo.