Head shape variations between populations of the sand fly Lutzomyia cruciata (Diptera: Phlebotominae) from two Neotropical biogeographic provinces

Lutzomyia cruciata is a sand fly species of medical importance with a wide distribution in America. In Mexico its distribution includes nine heterogeneous biogeographic provinces in ecological and biodiversity terms. The latter could represent a strong ecological pressure on the species, giving rise to phenotypic variation mainly in those functional traits that are determining for the species. In this study, we used a broad geographic sampling of Lu. cruciata and geometric morphometric techniques to assess variation in head shape in populations from two environmentally heterogeneous biogeographic provinces, Veracruz and the Yucatán Peninsula. We also tested whether morphological variation could be related to the climatic conditions across the two biogeographical provinces. We found that head shape revealed more differences among populations within provinces than between them. Such morphological head shape variation was not associated with bioclimatic or geographical variables in either province. This pattern of morphological variation in head shape is congruent with previous evidence on the wing shape of Lu. cruciata populations. Further studies of these and other populations using genetic markers are clearly needed to allow a more precise estimate of variation or differentiation in this sand fly vector.