Metaleurodicus variporus, John H. Martin, 2004

John H. Martin, 2004, Whiteflies of Belize (Hemiptera: Aleyrodidae). Part 1 — introduction and account of the subfamily Aleurodicinae Quaintance & Baker, Zootaxa 681, pp. 1-86 : 51-53

Metaleurodicus variporus sp. nov.

( Figs 28–32, 97–98)

PUPARIUM. Habitus. The immature stages develop in loose aggregations under leaves, most individuals having chosen feeding positions adjacent and nearly parallel to a major leaf vein, but not only the midrib. Visible wax secretion comprises fine, transparent filaments: each of the dorsal compound pores secretes a long and rather rigid filament, and these readily break off as length increases; the filaments issuing from the largest compound pores are visibly hollow and thicker than the remainder; a short, transparent, wax rod issues from each submarginal cup­shaped pore, to give the puparium a sparse fringe. Despite wax filaments, the feeding larval and nymphal stages are extremely cryptic, the leaf tissue being visible through the body. Margin. Outline rather narrowed cephalically ( Figs 28–32), 1.10–1.40 mm long, 0.68–0.90 mm wide (n=50), widest at abdominal segment IV/V. Margin smooth to slightly uneven, but may appear irregularly crenate if slightly downcurled (Fig. 98), not modified at thoracic or caudal tracheal openings. Dorsum. A series of fine lines run mesad from margin as far as the submarginal setal bases, revealed as corrugations when seen in relief through down­curling of the puparial margin (Fig. 98). Longitudinal moulting suture reaching puparial margin, transverse moulting sutures reaching submargin, the sutures sometimes difficult to discern distally. Segmentation well marked across subdorsum, from meso­/metathorax to abdominal segment VII/ VIII, with pro­/mesothoracic suture only distinct medially; abdominal segment VII half length of segment VI medially. Vasiform orifice ( Figs 28–32) cordate; operculum transversely rounded­rectangular, with a pair of fine setae present on its sinuate posterior margin; lingula head tongue­shaped, extending about half way from posterior margin of vasiform orifice to puparial margin, bearing 4 stout setae. Chaetotaxy. Anterior and posterior marginal setae present, anterior pair minute but posterior pair similar to caudal pair of submarginal setae. Outer submargin with 12 pairs of hair­like setae (Fig. 98), including nominal caudal pair which are somewhat longer than remainder. Dorsal disc setae restricted to eighth abdominal pair, anterior to vasiform orifice and adjacent to anterior corners of operculum. Pores. Cephalic and 6 pairs of abdominal compound pores present, of three variants, always at least two variants present in an individual ( Figs 28–32): large variant each ~40 µ m diameter (up to 50 µ m in one individual), robust and clearly cylindrical, usually presenting laterally or obliquely (Fig. 98) on slides; medium variant ~30 µ m, cup­shaped, often presenting axially or obliquely, when the basal loculi then resemble a stylised flower (Fig. 98); small variant ~20 µ m, usually presenting laterally. Cephalic compound pores always of the small or medium variant, 2nd and 4th abdominal pairs always of the large variant, 6th (posteriormost) abdominal pair always small, 1st and 5th abdominal pairs large or medium, 3rd abdominal pair may be any of the three variants; commonest abdominal combinations are LLSLLS ( Fig. 31, n=53) & MLMLMS ( Fig. 28, n=38), total n=118. Each compound pore with a short, truncate central process which, at most, protrudes only slightly beyond the pore mouth (Fig. 98). Outer subdorsum with a single row of cup­shaped simple pores (see habitus description), presumed to be the 8­ shaped type described by Russell (1965) but with the structure indistinct, fairly evenly spaced except where submarginal setae interrupt the row (Fig. 98). Remainder of dorsal disc smooth, except for scattered tiny simple porettes and larger quadrilocular pores (Fig. 98). Ven te r. Ventral abdominal setae underlying vasiform orifice, of similar length to it. Legs large, each two­segmented, with a single apical claw, sometimes relatively “larviform” in appearance (Figs 97b,c) but much larger in mature specimens (Fig. 97a), see discussion below. Antennae of mature specimens reaching mid­point of middle legs ( Figs 31, 97a): however those of many individuals considerably reduced, and when viewed laterally (Fig. 97c) they are much shorter than apical segment of foreleg, extremely corrugate; many others have completely vestigial antennae, appearing subcircular with only the apex distinct ( Figs 28–30, 32, 97b). Rostrum acute­triangular ( Figs 28–29).

MATERIAL EXAMINED. Holotype puparium, BELIZE, CFR, San Pastor track, on Lasianthaea fruticosa (Asteraceae) , 28.ii.1996 (J.H.Martin #6714) ( BMNH). Paratypes (all CFR, Martin coll.): 133 puparia, 15 third­instar larvae, 2 second­instar larvae, 6 adult females, tracksides in Las Cuevas vicinity, same host as holotype, 30.xi.1994, 28.ii.1996, 06.iii.1996, 04.vi.2002, 20.iii.2003, 22.iii.2003, 24.iii.2003 ( BMNH, BZ, USNM); 5 puparia, same locality, on Urera sp. ( Urticaceae ), 28.ii.1996; 7 puparia, 1 third­instar / puparial mid­moult, 1 third­instar exuviae, on? Euphorbiaceae , 23.iii.2003; 6 puparia, 1 third­instar larva (all slide­mounted) & 5 puparia, 3 third­instar larvae (dry on leaves), same locality, undetermined host, 20.xi.1994 (all BMNH).

ETYMOLOGY. The specific epithet is derived from the Latin, varius (meaning changeable or variable), reflecting the pronounced variability in the dorsal compound pores of the puparium, within populations.

COMMENTS. This species exhibits unusual developmental features, affecting the puparial legs, antennae and compound pores. The marked plasticity of size and, hence, form displayed by the compound pores is a feature that is not usual, but has been observed in a few other Aleurodicinae . The reason for the vestigial nature of the puparial antennae in some samples (see venter, above) is not certain, but a few specimens from reducedantenna samples have the antennae beginning to lengthen (Fig. 97c), and all post­emergence pupal cases have normal antennae (Fig. 97a). A similar phenomenon appears to affect the development of the puparial legs, with fully­developed legs only apparent in specimens that also have fully developed antennae ( Figs 31, 97a). It seems likely that the antennae and legs do not begin to expand towards their full length until some time after the third/fourth instar moult. There is no obvious correlation between antennal and leg development and the distribution of compound pore types. The holotype puparium has fully developed antennae and legs.

Caballero (1992) presented a description and puparial illustration of a species that is almost certainly M. variporus , from an ornamental plant in Guatemala, but listed it only as an undescribed member of the Aleurodicinae .

M. variporus may be distinguished from the other Metaleurodicus species known from Belize by use of the key, above.