The role of wing geometric morphometrics in the identification of sandflies within the subgenus Lutzomyia

The Lutzomyia subgenus (Diptera: Psychodidae) includes sibling species with morphologically indistinguishable females. The aims of this study were to analyse variations in the size and shape of wings of species within the Lutzomyia subgenus and to assess whether these analyses might be useful in their identification. Wings (n = 733) of 18 species deposited in Brazilian collections were analysed by geometric morphometrics, using other genera and subgenera as outgroups. Shape variation was summarized in multivariate analyses and differences in wing size among species were tested by analysis of variance. The results showed significant variation in the sizes and shapes of wings of different Lutzomyia species. Two clusters within the Lutzomyia subgenus were distinguished in analyses of both males and females. In Cluster 1 (Lutzomyia ischnacantha, Lutzomyia cavernicola, Lutzomyia almerioi, Lutzomyia forattinii, Lutzomyia renei and Lutzomyia battistinii), scores for correct reclassification were high (females, kappa = 0.91; males, kappa = 0.90), whereas in Cluster 2 (Lutzomyia alencari, Lutzomyia ischyracantha, Lutzomyia cruzi, Lutzomyia longipalpis, Lutzomyia gaminarai and Lutzomyia lichyi), scores for correct reclassification were low (females, kappa = 0.42; males, kappa = 0.48). Wing geometry was useful in the identification of some species of the Lutzomyia subgenus, but did not allow the identification of sibling species such as L. longipalpis and L. cruzi.