Pealius Quaintance and Baker

Gill, Raymond, 2012, A preliminary report on the World species of Bemisia Quaintance and Baker and its congeners (Hemiptera: Aleyrodidae) with a comparative analysis of morphological variation and its role in the recognition of species Raymond Gill, Insecta Mundi 2012 (219), pp. 1-99 : 6-7

Pealius Quaintance and Baker , the vasiform orifice is closed posteriorly by a sclerotized ridge, and the lingula is short, spinose and generally covered in its entirety by the operculum, although the species Pealius azaleae (Baker and Moles) is an exception. The genus Aleyrodes Latreille is very similar in appearance to species in the afer group, except that the vasiform orifice tends to be broader and shorter, with a shorter lingula. Aleyrodes spiraeoides Quaintance , a species apparently native to western North America, normally has short dorsal seta, but specimens are known where these setae are enlarged and elongated, as they are in the tabaci and afer complexes. Adults of A.

spiraeoides are also similar to adults in the afer group in those cases where the adults are known.

Even though there is a great similarity in the morphology of Aleyrodes with some of the Bemisia groups, DNA analysis has shown that they probably are not closely related ( Gill and Brown 2010),

and their similarities may be due either to convergence or to the retention of ancient ancestral characters.

In order to understand the morphology of the Bemisia species , it is necessary to begin with the puparial morphology of B. tabaci populations of A and B, with inclusion of characteristics of the other groups for comparison. Economically, species within the tabaci complex and the afer complex have been of importance to agriculture and horticulture, and they have certain characters that separate them. This morphological overview does not necessarily include other species within Bemisia . The tabaci complex puparia are smaller than those in the afer complex, have a more tapered ovoid appearance, long caudal setae, certain setal placement patterns, and pore/porette combinations that are adjacent to each other and occur with no particular alignment to the margin. The afer complex puparia are larger, are more nearly circular rather than ovoid, have short caudal setae, different setal placement patterns and pore/porette combinations that are mostly nonadjacent and aligned with the porettes in each pair closer to the margin.

Figures 1-80, in conjunction with the text, will illustrate what appear to be species complexes and species groups within the genus Bemisia . It will also explain some of the morphological problems and how they bear on how the genus and its congeners are treated taxonomically. The first thirteen illustrations ( Fig. 1-13) are of Bemisia tabaci sensu strictu and show morphological structures,

variations in morphology, variations in placement and size of various dorsal setae, and the varying numbers of minute submarginal setae. Also, several specimens of B. tabaci are included that were formerly described as other species ( Fig. 12-13).

In Fig. 1, the major body setae of the B. tabaci puparium are indicated. There are three pairs of setae that are typically found in most species of whiteflies. These are the caudal setae (CS), the anterior marginal setae (AMS), and the posterior marginal setae (PMS). There are six pairs of subdorsal setae (DS1-DS6). These setae may all be small and short, as in Fig. 2, 6 and 7, and are so primarily when the host leaf is smooth. If the host leaf has varying degrees of hairiness, these subdorsal pairs may become long and spine-like. Not all setal pairs enlarge in all cases; the anterior

(cephalic pair) will often enlarge when none of the others do. The general distribution of enlarged setae is from anterior to posterior, although this order is variable. Enlargement patterns on any given puparium can vary amongst individuals within the same population. Usually both setae in a right/left pair enlarge simultaneously, but on rare occasions only one will enlarge. In the case of subdorsal seta on the metathorax (DS4), if the majority of the other subdorsal setae do not enlarge,

DS4 cannot be found anywhere in the vicinity of its normal enlarged location. There are five pairs of submarginal setae (PSMS1-PSMS5) on the abdomen that are counted anteriorly from a position just anterior to seta PMS (e.g., Fig. 3). Setae PSMS1-PSMS4 are always roughly aligned in a shallow arc.

Seta PSMS5, unlike the other submarginal setae, can become enlarged as in the subdorsal setae. If unenlarged, setae PSMS5 usually lines up in the shallow arc with the other PSMS setae. If PSMS5

becomes enlarged, its position will always be shifted medially into the shallow arc alignment occupied by most of the subdorsal setae except DS5. There are three or four anterior submarginal setae

(ASMS1-ASMS4). The ASMS setae do not seem to enlarge or shift position in the tabaci group. In the afer and asterobemisia groups, the submarginal and dorsal body setae rarely enlarge (but see Fig. 17,

23), and apparently the puparia typically respond to environment influences by producing different kinds of protuberances, varying from simple conical to star-shaped constructions. The afer and asterobemisia groups generally have more submarginal setae than in the tabaci group, particularly in the area between the second abdominal segment and the tracheal furrow.

All of the described species in Bemisia exhibit pore-porette combinations; in the illustrations the pore is represented by a dark rimmed circle and the porette is represented by a small dot surrounded by a much bigger, lighter circle. The pores are given group alignments in Figure 1 (SDP, SMeP). In the tabaci complex, each pore and porette are immediately adjacent, with only rare exceptions. The alignment of the pore-porette pair is apparently random with respect to the margin of the puparium.

In the afer and asterobemisia groups, however, the pore and porette pair is usually always separated by a distance considerably larger than the diameter of the pore, and the pore and porette pair are nearly always aligned with the porette closer to the body margin, particularly marginally.

The total number of pore-porette pairs is much greater in the afer and asterobemisia groups than in the tabaci complex. For instance, there is one pair of pore-porettes on the first abdominal segment between the subdorsal seta DS 5 in the tabaci complex, but in the afer-asterobemisia groups there are usually two pairs in this position. There are, however, intermediate forms of uncertain generic placement that may have two pairs of pore-porettes on the first abdominal segment, but adjacent pores and porettes with random alignment to the margin, such as occurs in species formerly in the genus Neobemisia . There is also one population of afer complex specimens on Hypericum reflexum

L.f. ( Hypericaceae ) from the Canary Islands (not illustrated) in which the pore/porette pairs are present on the first abdominal segment, but each individual may have 0–2 pairs on either side of the segment, a situation so far unseen in other afer complex populations, where the numbers are usually constant on each side of the segment. Also some specimens from the United States and Mexico may have three pairs of pore/porettes on the segment.