Determination of sexual dimorphism in the puparia of four whitefly pest species from India (Hemiptera: Aleyrodidae)

Abstract: We evaluated sexual dimorphism in puparia of four whiteflies, viz., Aleyrodes sp. on Oxalis corniculata (Oxalidaceae), Bemisia tabaci (Gennadius, 1889) on Solanum melongena (Solanaceae), Dialeurodes delhiensis David & Sundararaj, 1992 on Ficus virens (Moraceae), and Trialeurodes vaporariorum (Westwood, 1856) on Phaseolus vulgaris (Fabaceae), based on a set of ten morphometric characters analysed by univariate and multivariate statistics. Differences between males and females in means of the selected ten characters and in several character ratios were highly significant. The multivariate analyses including principal component analysis (PCA) and canonical discriminant analysis (CDA) revealed that sex can be reliably identified in puparia in these species based on a combination of characters such as the length and width of puparia irrespective of species; length of caudal furrow for Aleyrodes sp., D. delhiensis and T. vaporariorum; length of the seventh abdominal segment for D. delhiensis and T. vaporariorum; width of operculum alone for Aleyrodes sp.; and length of vasiform orifice (LVO) alone for B. tabaci; and the combination of some of their ratios. Identification of puparium sex is important for studies in taxonomy, biology and pest management of whiteflies. The results of this study show that morphometrics can provide a useful tool for its diagnosis and accurate identification.

Key words: Sternorrhyncha, Aleyrodomorpha, Aleyrodoidea, whiteflies, puparium, morphometrics, multivariate analyses, identification