ANALYSIS OF MORPHOLOGICAL VARIATION IN DISTINCT POPULATIONS OF BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE)

Morphological characters of whiteflies, Bemisia spp., from 17 populati ons from disparate locations worldwide were compared. Historically, ch aracters of 4th instars (pupae) are used for separating Bemisia spp. W e assessed variability in the following characters of the 4th instar: anterior submarginal setae, anterior and posterior wax fringes, dorsal setae, posterior submarginal setae, caudal setae, and tracheal folds. Anterior submarginal setae 4 (ASMS 4) were generally, but not always, absent in B. argentifolii Bellows & Perring and B biotype populations , and in most non-A/non-B biotypes (E, K, L, P, and Q). However, ASMS 4 were found in A biotypes, in the N biotype, and in B. hancocki. Dors al setal pair 4 was absent in most populations, and the lengths of dor sal setal pairs 1, 2, 3, 5, and 6 varied on individuals from several p opulations. Anterior wax fringes were highly variable in length and wi dth in all populations. With the exception of the Nepal (P biotype) po pulation, posterior wax fringes extended beyond the borders of the cau dal setae in all individuals examined. Although posterior submarginal setal pair 5 (PSMS 5) was short in most individuals examined, these se tae were elongated in a few individuals from 5 populations. Phylogenet ic analysis did not resolve most-parsimonious trees. Our observations indicate that morphological characters of pupae are not useful alone f or classifying individuals from B. tabaci or B. argentifolii populatio ns.