Scymnus (Pullus) syoitii Sasaji, 1971

Poorani, J., Anuradha, C., Thanigairaj, R. & Mol, P. Prashina, 2024, Coccinellid predators of mealybugs infesting banana in South India, including a new species and a new record of Scymnus Kugelann (Coleoptera: Coccinellidae), with notes on other natural enemies, Zootaxa 5419 (4), pp. 525-544 : 538-543

Scymnus (Pullus) syoitii Sasaji, 1971

( Figs 8 , 9 )

Scymnus (Pullus) syoitii Sasaji, 1971: 146 .

Brief description. Length: 1.10–1.30 mm; width: 0.70–0.90 mm. Form narrow and elongate oval, dorsum weakly convex with dense white pubescence; lateral margins of elytra with few long, erect setae interspersed with shorter ones. Dorsum usually pale yellow ( Fig. 8f, h ), rarely darker reddish brown ( Fig. 8g ), basal part of elytra with darker infuscate area. Head ( Fig. 9a ) broad with small eyes, interocular distance a little more than 3/5 th of head width. Antenna ( Fig. 9b ) with 11 antennomeres. Prosternal carinae distinctly and somewhat abruptly divergent posteriorly around middle ( Fig. 9c ). Abdominal postcoxal line complete, strongly curved, anteriorly punctate, smooth and impunctate near posterior margin ( Fig. 9d, e ). Male genitalia ( Fig. 9f–h ) with penis having a distinct capsule ( Fig. 9h ), penis guide elongate triangular in ventral view ( Fig. 9g ), parameres and penis guide subequal in length, apices of parameres with few short hairs ( Fig. 9f, g ). Female genitalia ( Fig. 9i ) and spermatheca ( Fig. 9j ) as illustrated. See Sasaji (1971) for detailed description.

Immature stages. Larva ( Fig. 8a–d ) creamy white with white waxy filaments, always found in association with banana root mealybug colonies. Pupa ( Fig. 8d, e ) elongate, creamy white, somewhat bereft of waxy filaments.

Material examined. India: Tamil Nadu: Mullikarumbur, N10°49’34.39” E078°36’41.69”, Ex. Root mealybug complex on banana, 18.ix.21, 22.xii.21, R. Thanigairaj ( ICAR-NRCB: 9); INDIA: I.I.S.C., Bangalore, Karnataka / vii.1992, Sp. no. 44/ex Planococcus citri IIE 22763/ Scymnus (P.) sp., det. R.G. Booth, 1993/Pres. by Int. Inst. Ent. B.M. 1993 ( BMNH: 2M (genitalia dissected), 1 unsexed).

Distribution. Japan; India (Karnataka; Tamil Nadu) (new record).

Prey / associated habitat. Predatory on banana root mealybug complex (comprising Geococcus? johorensis Williams , Geococcus sp. and Rhizoecus sp. ); Planococcus citri (label data).

Notes. Sasaji (1971) described it from Kyushu, Japan [see the holotype photo and details in Kyushu University Museum Database [Hiroyuki Sasaji Collection, Catalog no. SH005533, URL: http://db.museum.kyushu-u.ac.jp/ entomology/?wb=det&cl=31&it=5533]. It appears to be a unique and characteristic species of Scymnus in South India with a small, distinctly narrow and elongate oval form, head with a wide frons and small, broadly separated eyes, and prosternal carinae that are distinctly divergent posteriorly and the male genitalia are also diagnostic. The specimens collected from Tamil Nadu, fully match Sasaji’s (1971) description and the male genitalia also are almost identical to the illustrations given by Sasaji. The larvae were found to be predatory on banana root mealybug complex (comprising a mixture of Geococcus?johorensis , Geococcus sp. and Rhizoecus sp. ). Conspecific specimens collected in association with Planococcus citri from Bangalore, Karnataka, by the Commonwealth Institute of Biological Control-Indian Station (Bangalore) in the collections of BMNH were also examined. It is a new addition to the fauna of Scymnini of the Indian region.

Figures

FIGURE 8. Life stages of Scymnus (Pullus) syoitii Sasaji: a, c. larva feeding on banana root mealybug; b. larva on banana root; d. mature larvae and pupa in soil; e. pupa; f–h. adult.

FIGURE 9. Scymnus (Pullus) syoitii Sasaji: a. head; b. antenna; c. prosternal carinae; d. abdomen, male; e. abdominal postcoxal line; f–h. male genitalia: f. tegmen, lateral view; g. tegmen, ventral view; h. penis; i. female genitalia; j. spermatheca (enlarged).