Morphological discontinuous variation and disparity in Lutzomyia (Tricholateralis) cruciata Coquillett, 1907 are not related to contrasting environmental factors in two biogeographical provinces

Abstract

Lutzomyia cruciata (Diptera: Phlebotominae) is an important Leishmania vector with wide distribution in America. However, geographical patterns of morphological variation of populations along its longitudinal and latitudinal distribution are still unknown. In this work, we quantified morphological variation and disparity in 243 specimens (females) from nine sample groups of Lu. cruciata from two biogeographical provinces in Mexico: Veracruzan Province (five groups) and Yucatan Peninsula Province (four groups). We registered two linear morphometric data of a reproductive structure (spermatheca) and one landmark configuration for wing shape. Our questions were if intraspecific morphological variation and disparity are related to contrasting environmental factors in these two provinces. First, our results from canonical variates analyses of the spermatheca and wing shape revealed more differences among groups of specimens within a biogeographic province than between. Second, our regression analyses revealed that morphometric variation is weakly related to 20 environmental variables considered for the two biogeographic provinces. Levels of morphological disparity in the spermatheca and wing shape within the two provinces are the same regardless of environmental homogeneity in the Yucatan Province or heterogeneity in the Veracruzan Province. These patterns of morphological variation and disparity weakly correlated with environmental variables suggest that intraspecific variation in Lu. cruciata is not clinal within a province. Subsequent investigations will be required to elucidate suspected correlations of local discontinuous phenotypes with genetic divergence within a biogeographical province.