Acletoxenus indicus Malloch

Yu, Guoyue, Wu, Liang, Lu, Jinming & Chen, Hongwei, 2012, Discovery of a predaceous drosophilid Acletoxenus indicus Malloch in South China, with descriptions of the taxonomic, ecological and molecular characters (Diptera: Drosophilidae), Journal of Natural History 46 (5 - 6), pp. 349-354 : 351-353

Acletoxenus indicus Malloch

( Figures 1 and 2 )

Acletoxenus indicus Malloch, 1929 . Ann Mag Nat Hist, 31: 545.

Description

Some characters not mentioned in Malloch (1929) are given below. Measuring in 5♂ and 5♀ adults: BL 1.96–2.22 mm in ♂, 1.94–2.35 mm in ♀; ThL 1.10–1.25 mm in ♂, 1.08–1.30 mm in ♀; WL 2.08–2.27 mm in ♂, 2.12–2.30 mm in ♀; WW 1.02–1.05 mm in ♂, 1.04–1.13 mm in ♀. Male terminalia: epandrium protruded anterad and posterolaterally much protruded ventrad, with c. 20 short setae and pubescence ( Figure 1C ). Cercus small, separated from epandrium, pubescent and setigerous ( Figure 1C ). Surstylus almost entirely fused with epandrium, with three small setae apically on inner surface ( Figure 1C ). Hypandrium anteriorly narrow and laterally broad, with five or six setulae per side, basally with a narrow, anterad rod-like process, submedially with lobe-like process bearing four or five setulae ( Figure 1D ). Paramere bilobed, sclerotized and pointed apically, lacking sensilla, basally fused to aedeagal apodeme ( Figure 1D ). Gonopods strongly curved dorsad, pointed apicolaterally ( Figure 1D ). Aedeagus basally with two pairs of lobe-like processes ( Figure 1D , lop): one of them small; the other curved dorsad and pointed apically ( Figure 1D ), apically with gracile membranous tube ( Figure 1D ). Aedeagal apodeme small, lobe-like ( Figure 1D ).

Specimens examined

CHINA: 4♂, 2♀ ( SCAU, nos. 121002–121007), Guangzhou , Guangdong, 23 ◦ 09 ′ N, 113 ◦ 21 ′ E, 8 September 2003, from variegated laurel ( Codiaeum variegatum ), X.M. Wang ; 11♂, 6♀ ( SCAU, nos. 121008–121024), Zhanjiang , Guangdong, 21 ◦ 16 ′ N, 110 ◦ 21 ′ E, 17 April 2005, from Hibiscus sp. , S.X. Ren ; 2♂, 2♀ ( SCAU, nos. 120998–121001), Qionghai , Hainan, 19 ◦ 16 ′ N, 110 ◦ 28 ′ E, 19 June 2009, reared from immature stages collected on guava ( Psidium guajava ), G.Y. Yu .

Life history and habits

Larvae of A. indicus have been observed preying on whitefly nymphs in the following plants Acalypha wilkesiana, Terminalia catappa, Codiaeum variegatum , Psidium guajava , Hibiscus rosa-sinensis . In Hainan Province, China, A. indicus larvae prey on nymphs of spiralling whitefly Aleurodicus dispersus . The egg of A. indicus is covered with a white waxy incrustation which is roughened with irregular or indistinct reticulate markings. The eggs are laid singly upon the leaf surface, adjacent to the late-stage nymph or pupa of whitefly. The larva is translucent white in its early stages, and then changes to greenish as the body contents are visible through the transparent integument ( Figure 2B,C ). The larva is inactive because the colony of whiteflies around it provides sufficient food for its maturity. Noticeably, sometimes there are several larvae on one leaf. The larva secretes a mucilaginous fluid that covers the whole body in the early stages, leading to the body of larva, particularly on the dorsum, being covered with particles of extraneous matter in the later stages. Many mature larvae carry a large number of egg shells or wax of Aleurodicus dispersus , and these structures may also be found upon the puparium ( Figure 2C ). Pupation occurs on the underside of the leaf. The ventral surface of the puparium is flat and adheres strongly to the leaf surface. The greenish colour of the body contents is observable in the early pupal period, and then the large, deep red eyes of the developing pupa are also observable. Emergence is effected by the breaking away of the distinct lid at the anterior end. The empty puparium is white ( Figure 2D ).

Distribution

China (Guangdong, Hainan; new record); India.

Figures

Figure 1. Acletoxenus indicus Malloch, male. (A) Head; (B) wing; (C) epandrium (epan), cercus (cerc) and surstylus (sur) (lateral view); (D) hypandrium (hypd), paramere (pm), aedeagus (aed) and aedeagal apodeme (aed a) (lateral view). Scale bars: 0.1 mm.

Figure 2. Acletoxenus indicus Malloch. (A) Adult; (B) larvae (green) preying upon spiralling whitefly on the underside of guava leaf; (C) coarctate pupae of spiralling whitefly; (D) puparium after eclosion. [This figure can be viewed in colour online.]