Aleuropleurocelus hyptisemoryi Gill

Polaszek, Andrew & Gill, Raymond, 2011, A new species of whitefly (Hemiptera: Aleyrodidae) and its parasitoid (Hymenoptera: Aphelinidae) from desert lavender in California, Zootaxa 2750, pp. 51-59 : 52-56

Aleuropleurocelus hyptisemoryi Gill sp.n.

( Figs 1 –4)

Puparium: Habitus. Black. Body oval or elliptical, with six to eight slightly lobate to strongly conical projections on each side along the apparent margin pointing outward and upward, often giving the body a serrated appearance. Body 600 to 800 microns long (avg. 626) by 400 to 590 microns wide (avg. 475). With a thin white band of wax bordering the true margin, not visible in dorsal view due to the overhang of the false margin. Dorsum in side view basically flat, but venter strongly convex, the whole pupal case resting above the actual leaf surface because the host leaf has thickened veins and thick duff (a felt-like tomentum composed of dendritic hairs) over the entire lower surface. As a possible adaptation to this, the rostrum in the puparium is long, and five elongated ventral thoracic protrusions, and possibly the legs, reach downwards through the duff in order to anchor on to the leaf surface.

Morphology. Puparium typical of the genus Aleuropleurocelus , with the true margin between dorsum and venter having a transverse width narrower than the total width of the body and thus not visible in dorsal view. True margin with shallow, irregular crenulations numbering approximately 75 to 100, actual total count on any given specimen not discernable. Differentiated crenulations at thoracic furrows also not discernable. Deflexed portion of dorsum adjacent to true-marginal crenulations with rows of one to three clusters of dark granulations perpendicular to the margin, usually with about two rows per four or five crenulations. Chaetotaxy - anterior and posterior marginal setae apparently absent, but might have been broken off during the slide-mounting process, hidden among the folds and creases of the deflexed true margin, or represented only by minute setal bases, although one specimen appears to have one anterior marginal seta 70 microns long (see Fig. 2 but also descriptions of the other instars); Second and third thoracic setae often fleshy and apically flattened or broadened, each 25 to 45 microns long (avg. 36) and situated on a broad tubercle, pairs with their basal tubercles almost contiguous on the 2nd and 3rd thoracic segments, the 2nd segment pair further apart than the 3rd segment pair; setae on the cephalic/prothoracic locations apparently not present, probably each represented only by a setal base. A pair of setae, each 45 to 62 microns long (avg. 46), present anterolaterally to the vasiform orifice on the 8th abdominal segment; a caudal pair, each 38 to 53 microns long (avg. 52) present at the posterior end of the pupal case. Conical, papilla-like structures each up to 10 microns in diameter present along the false margin, each usually accompanied by a single minute disc pore. Associated with, but distal to, the same locations as the papillae, the derm at the false margin forms six to eight pairs of rounded to broadly pointed projections, each up to 18 microns long, from abdomen to thorax, giving the puparium a lobate to serrated appearance; these projections apparently becoming longer as the pupa ages. Pores - Dorsal pores of simple discoidal type, present in three longitudinal rows on each side: a longitudinal row adjacent to the false margin with pores often situated near or next to the papillae; a pair of pores present subdorsally on abdominal segments 2−4, and the 8th abdominal segment anterolateral to the vasiform orifice, readily discernable on older specimens but not so on younger pupae; and a variable number of pores present in a curved row on each side of the abdominal subdorsum, approximately overlying the true margin. Dorsal discoidal pores sparsely present on cephalothorax in no particular arrangement. Puparium dorsal surface after molting relatively smooth, but becoming covered with heavy granulation as the pupa ages. Vasiform orifice - Orifice cordate, tapering broadly posteriorly, surrounded by a nearly circular, sclerotized band. Posterior floor of orifice with thickly set microspines. Operculum shape difficult to discern on slide-mounted specimens but appears to be lobed in some specimens, with various striations and ridges. Lingula not observed. Transverse molting suture reaching nearly to false margin, the lateral ends turning forwards slightly. Venter - covered with close-set microspines except at areas where legs and mouthparts occur; with five protuberances, two pairs located approximately underneath the dorsal thoracic setae, one protuberance situated across the midline under the meso- and metathoracic sutures; antennae broad throughout, tapering abruptly at apex, number of segments not discernable, often not visible due to crowding between the first pair of legs and the folding of the true margin, but easily discernable in teneral specimens.

Third instar: Morphology. Description based on one set of stacked 1st, 2rd and 3rd instar exuviae, a condition common to many melanistic whiteflies where the exuviae are retained over the dorsum of each successive instar: including the pupa, and eight specimens singly mounted, the single specimens all folded back with the cephalothoracic area over the abdominal area, obscuring many details. Length of body 402 microns. Dorsal meso and metathoracic setae 38 microns; caudal and 8th abdominal setae 40 microns. Anterior and posterior marginal setae apparently absent. Vasiform orifice oval; operculum cordate, tapering posteriorly to a flattened apex; lingula bulbous apically and covered with microsetae. With round, slightly raised, evenly spaced protuberances present dorsally around margin, numbering 18 or more on the abdomen and continuing on to the cephalothorax, the exact number not discernable due to the folding-over of the cephalothorax. Six pairs of papillae present submarginally on abdomen, but not discernable on cephalothorax.

FIGURES 3–4. Aleuropleurocelus hyptisemoryi : (3) dorsal view of the puparium on host, note dense duff covering the leaf surfaces and discarded 1st to 3rd exuviae stacked on top of the puparium; (4) dorsolateral view showing exaggerated lateral protrusions found in some individuals, possibly a development in older pupae nearing adult emergence.

Second instar: Morphology. Description based on one set of stacked 1st, 2nd and 3rd instar exuviae. Length of body 282 microns. Dorsal setae not found due to poor condition of the specimen, but 8th abdominal and caudal setae each approximately 38 microns long. Anterior and posterior marginal setae apparently absent. Vasiform orifice oval; operculum cordate, tapering posteriorly to a flattened apex; lingula bulbous apically and covered with microsetae. With round, slightly raised protuberances present dorsally around margin. Other characters not discernible in specimen at hand, due to the overlapping of the exuviae of three stages.

First instar: Morphology. Description based on one set of stacked 1st, 2nd and 3rd instar exuviae. Body 210 microns long. With 5 to 6 pairs of submarginal setae, each 28 to 35 microns long; caudal setae 38ų long, 8th abdominal setal bases present but setae broken off. Anterior and posterior marginal setae apparently absent. Vasiform orifice oval; operculum cordate, tapering posteriorly to a flattened apex; lingula bulbous apically and covered with microsetae. Tibiotarsal length 43 microns. Other characters not discernible in specimen at hand, due to the overlapping of the exuviae of three stages.

Adult: Morphology. Adults typically aleyrodine, with no distinctive anatomical structures except for rostral and ovipositor lengths. Body of male 1000 to 1004 microns long, female 1250 to 1320 microns long. Male clasper (paramere) 125 to 128 microns long, unadorned and without subapical spines or teeth. Female ovipositor unusually long, 372 to 409 microns, apparently adapted for reaching through heavy duff and leaf hairs to the surface of the host leaf. Rostral lengths also long, 300 microns in male, 372 to 414 microns in female, apparently for the same reason. Metatibial lengths 279 to 290 microns in male; 342 to 348 microns in female. Third antennal segment 133 to 140 microns long in male, 150 microns in female. Metatibiae each with 15 to 17 setae in comb; metatibial and mesotibial brushes not evident. Upper and lower compound eyes separated narrowly by one ommatidium.

Material examined. Slide-mounted specimens: Holotype: U.S.A., California, Imperial County, Shell Canyon, 17.vii.1995, coll. K. Hoelmer #32, on desert lavender ( Hyptis emoryi ); holotype one of three specimens on slide and marked with two arrows.

Paratypes: California, Imperial County, Shell Canyon, 17.vii.1995, coll. K. Hoelmer #32, on desert lavender ( Hyptis emoryi ), 6 specimens on 2 slides (including holotype); California, Riverside County, Deep Canyon 33º38’N 116º23’W, 25.iii.2009, coll. A. Polaszek on Hyptis emoryi , 34 pupae, some with early exuviae still attached, on 4 slides; California, Riverside County, Palm Desert, Living Desert Museum, 10.vi.1997, coll. K. Hoelmer #20, on desert lavender, 15 pupae, eight 3rd instars, three male and three female adults on 6 slides; California, Riverside County, Palm Springs, Agua Caliente Indian Reservation, 27.ii.1998, coll. E. Reevers, on Hyptis emoryi , 12 specimens on two slides (plus numerous unmounted specimens on original plant material).

Botanical collections: puparia ex California Dept. Food & Agriculture Herbarium, all on Hyptis emoryi , no slides made: California, Imperial County, Imperial Wildlife Refuge, 1943, coll. F.B. McMurray 1285; California, Riverside County, 3 mi. E/O Indian Wells on Bradshaw Trail, 2.xi.1982, coll. J. Johnson and D. Barbe; California, San Diego County, East side Coyote Canyon (Borrego Springs), 4 Apr. 1993, coll. J.A. Hart and G.F. Hrusa.

Specimen depositions. The slide containing the holotype puparium will be housed in the California State Collection of Arthropods, at California Department of Food and Agriculture, Plant Pest Diagnostic Center, Sacramento California, U.S.A.; paratype slides will be divided between the above location; the Systematic Entomology Laboratory, Beltsville, Maryland, U.S.A.; and the Natural History Museum, London, U.K.

Distribution. Known only from extremely arid desert locations in Imperial, Riverside and San Diego counties in southern California.

Host plants. Known only from desert lavender, Hyptis emoryi [ Lamiaceae ]

Discussion. A. hyptisemoryi is the only known member of the genus with submarginal papillae, in which respect it resembles the species-group of Tetraleurodes acaciae (Quaintance) . Representatives of Aleuropleurocelus are very common throughout the desert areas adjacent to locations where A. hyptisemoryi has been collected. Several species, probably some still undescribed, are involved, but none has submarginal papillae, and in other Aleuropleurocelus species the only lateral protrusions of the false margin occur adjacent to the apex of the transverse molting suture rather than adjacent to the various papilla sites. The genus is poorly understood. Several of the type specimens of California species have apparently been lost. Attempts to obtain the types from the private collection of E.A. Drews have been unsuccessful. Indications are that the puparia tend to change drastically in overall appearance as they become older. The two illustrations of the puparia of A. hyptisemoryi shown here ( Figs 1 and 2 ) are partial evidence for this. The final appearance of the pupae may be affected by environment also, since the very large conical projections on specimens from the Living Desert locality had not developed in other nearby populations, even in the type locality population just a few miles away. Papillae similar to those in A. hyptisemoryi occur in species in the genus Tetraleurodes , and there is some concern that there may be some intergrades between members of Aleuropleurocelus and Tetraleurodes . Also due apparently to the deep duff covering of the leaf, the venter of the pupal case has five long, tubercular structures that apparently help to maintain contact with the true leaf surface. Adults of A. hyptisemoryi differ from most other local aleyrodine whiteflies in the greater length of the rostrum and female ovipositor, probably an adaptation for feeding and egg-laying through the deep duff and protruding leaf veins produced over the entire leaf surface of the host plant. One other California whitefly adult female also has a long ovipositor, Aleurotithius timberlakei Quaintance & Baker , probably due to closely set leaf hairs on its host, but that species belongs to the tribe Trialeurodini and is not closely related to Aleuropleurocelus .

Figures

FIGURE 1. Aleuropleurocelus hyptisemoryi. Left side of puparium showing anatomical details of holotype, depicting relatively shallow development of projections as seen in younger specimens and specimens from the type locality and elsewhere.

FIGURE 2. Aleuropleurocelus hyptisemoryi. Left side of puparium showing anatomical details of a paratype, depicting advanced development of conical projections around the false margin as found in some specimens from the collection at the Living Desert Museum, Palm Desert, Riverside County, California.