Asterochiton aureus Maskell, 1879

Martin, Nicholas A., 2020, Revision of the whitefly genus, Asterochiton Maskell (Hemiptera: Aleyrodidae) from New Zealand, a study of intraspecific variation, Zootaxa 4859 (3), pp. 301-341 : 315-318

Asterochiton aureus Maskell, 1879

Figures 6 A–G.

Asterochiton aureus Maskell 1879: 216 , pl. 7, fig d; 1881; 301.

Aleurodes melicyti Maskell 1890: 174 , pl. 13, figs 21–24.

Aleyrodes (Asterochiton) aurea (Maskell) , Cockerell, 1902: 282.

Aleyrodes (Asterochiton) aureus (Maskell) , Kirkaldy, 1907: 47; Quaintance, 1908: 5.

Dialeurodoides aureus (Maskell) , Quaintance & Baker, 1914, pp.98–99, pl. 37, figs 7–11.

Asterochiton aureus (Maskell) , Quaintance & Baker, 1915, p. xi; Sampson, 1943: 208; Russell, 1948: 7–8; Dumbleton, 1957, pp. 147–149, figs. 6–8, Designated Lectotype from Maskell collection.

Diagnosis. The distinctive feature of this species is the presence of large pores on the dorsum and many being concentrated in four radial lines associated with ridges on the dorsum.

Puparium ( Figs. 6 A–C). Sub-circular; pale cream to orange with dark brown median area; found on the under surface of leaves; few to high density per leaf; widest at abdominal segments II & III; emarginated at thoracic and caudal tracheal pores. Lectotype length 1.15 mm, range 1.10–1.50 mm (mean 1.29); width 1.04 mm, range 1.00– 1.45 mm (mean 1.20). Caudal and thoracic tracheal pores invaginated, comb at the base with 3–6 teeth ( Fig. 6 E–F). Margin is smooth but appears to be finely crenulated ( Fig. 6 E–F), 8–10 crenulations per 0.1 mm.

Dorsum. Finely sculptured ( Fig. 6B ). Central area raised like a rugged hill with four radial ridges along the lines of large pores and a ridge along the line of the caudal furrow ( Fig. 6C ). Submarginal area width, 30 µm, range 15–50 µm and to the line of large pores that separate it from the dorsal disc, 60 µm, range 30–100 µm. On the disc are four radiating rows of similar large pores, two above the thoracic tracheal folds and two on the abdomen just posterior to the transverse moulting suture. Similar pores are present on the anterior cephalic area of the disc in front of the cephalic ridge and a few on either side of the caudal furrow. Smaller pores are on the central discal area of the cephalothorax and abdomen. Abdominal segment VII median length 35 µm, range 28–50 µm, less than half median length of segment VI ( Fig 6D ). The abdominal intersegmental boundary VI–VII is sharply defined in the puparium, but in the 4 th instar larva it is weakly defined and the cuticle is thin and stippled. Transverse moulting sutures extend into subdorsal area. Pro-mesothoracic and meso-metathoracic sutures, and abdominal segmentation prominent, reaching subdorsal area. Vasiform orifice located anterior of caudal tracheal opening by two times of its own length. Caudal furrow is narrow and well defined and within a brown ‘ridge’.

Vasiform orifice ( Fig. 6D ). Subtriangular; length 75 µm, range 65–93 (mean 79), width 58 µm range 50–75 µm (mean 61); open and acute posteriorly; floor reticulated; operculum sub-trapezoidal, covering just over half of the length of the orifice, length 35 µm, range 30–43 µm (mean 37), width 40 µm, range 40–58 µm (mean 48); lingula slightly constricted near base, apex expanded and bluntly pointed or rounded at tip, exposed, not reaching the posterior margin of the vasiform orifice, length 40 µm range 33–55 µm (mean 45), two subapical setae present, 17 µm, range 12–20 µm.

Venter. Thoracic tracheal and caudal folds present; caudal fold may be partly hidden under sculpture supporting the caudal furrow; tracheal fold with stipples along its inner length, caudal fold with a different form of stippling along its whole length. Legs and antennae present, basal and terminal segments of legs 2 and 3 have one tiny seta ( Fig. 6G ). Ventral setae 18–30 µm long, 75–90 µm apart, near the anterior margin of the vasiform orifice. Anterior abdominal spiracles on segment II, posterior spiracles near vasiform orifice. Adhesive sacs seen in 4 th instar larva.

Chaetotaxy. Cephalothoracic seta 1, when present, small, 8–22 µm; abdominal seta 1 when present, small, 20–23 µm; abdominal seta 8, tiny, 5–12 µm, setae anteriad of vasiform orifice. Cephalothoracic lateral setae submarginal, setae 1–8, tiny, about 10–20 µm, five setae anterior to thoracic pore, three between the pore and the transverse suture. Abdominal lateral setae 2, 4–8, tiny, 5–12 µm; setae may be either subdorsal (mainly on larva) or submarginal on puparium. Caudal setae, tiny, 5–18 µm. Anterior and posterior marginal setae often larger than lateral setae; anterior marginal setae, mean length 15 µm, range 10–23 µm; posterior marginal setae, mean length 20 µm, range 10–30 µm.

Material examined. Lectotype: Pupal case on slide mount in Maskell collection, Labelled Aleurodes melicyti, 1889 W.M.M. and Asterochiton aureus Mask. TYPE Lectotype cf. Dumbleton 1957: 149. Now held in NZAC.

Other material: 2 puparia on one slide, NN, Ruby Bay, January 1952, Dumbleton, on Melicytus . NB. Other puparia and larvae collected in January and February 1952 were not suitable for detailed examination; 4 puparia (slides 79-69b1, 79-69b2), AK, Waitakere Ra., Bethels, Goldies Bush, 25 February 1978, B.M. May, on leaves of Melicytus ramiflorus ; 4 puparia (slide 91-193), HB, White Pine Bush Reserve, 20 June 1991 C.F. Morales, ex Melicytus ramiflorus ; 4 fourth instar larvae (slide 01-031), AK, Waitakere Ra., Fletcher Tk., 24 February 2001, N.A. Martin, Melicytus ramiflorus underside of leaves; 6 puparia (slide 02-202a), AK, Waitakere Ra., Rangemore Tk., 1 September 2002, N.A. Martin, Melicytus macrophyllus underside of leaves.

All specimens deposited in NZAC (Auckland, New Zealand) .

Host plants. This species has been found on the leaves of shrubs of two species of Melicytus (Violaceae) , M. ramiflorus J.R.Forst. & G.Forst. and M. macrophyllus A.Cunn ..

Distribution. The species has been found in the North and South Islands of New Zealand and is common in the Auckland Region.

Remarks. The only setae on the puparium recorded by Dumbleton (1957) were the posterior marginal setae, eighth abdominal setae and the caudal setae ( Dumbleton, 1957, Fig. 7 ). Re-examination of the slides has revealed that anterior marginal setae and many tiny setae are present on the cephalothorax and abdomen. Some specimens have a small cephalothoracic discal seta 1. First abdominal setae are on specimens from only one locality, Fletcher Track, Waitakere Ranges, Auckland. This is an example of the localised variability seen in the genus.

The numbers of lateral setae seen depend on the condition of the specimen. They are more likely to be seen on 4 th instar larvae than puparia.

Figures

FIGURE 6. Asterochiton aureus Maskell, 1879.A. Dorsum line drawing, B. Dorsum slide mount, C. Puparium on leaf of Melicytus ramiflorus (Violaceae), note the ridges associated with the radial rows of large pores. Photograph by Tim Holmes, Plant & Food Research, D. Abdominal segments VI and VII, and vasiform orifice, E. Caudal pore, note the large pores, tiny caudal setae, and abdominal lateral setae 7 & 8, F. Thoracic tracheal pore, tracheal fold with stippling, large pores, G. Antenna and legs.

FIGURE 7. Asterochiton cerata (Maskell, 1896) puparium. A. Dorsum line drawing, B. Dorsum slide mount, C. Live larvae and puparia covered in white wax on the underside of Lophozonia menziesii (Nothofagaceae) leaf, D. Abdominal segments VI, VII and VIII, note the stippling on VII, E. Vasiform orifice, lingula setae, F. Caudal pore and caudal setae, G. Antenna and legs, H. Thoracic tracheal pore and fold, cephalothoracic lateral setae, I. Abdominal lateral setae in submargin and posterior marginal seta, J. Cephalic lateral setae in submargin and anterior marginal seta.