Exochorionic pattern of ten sand fly species (Diptera: Psychodidae: Phlebotominae) from Mexico

Phlebotomine sand flies are of biological importance because of their role as vectors of several pathogens. Morphological identification faces challenges to separate related species; therefore, the study of immature stages, as the egg and its exochorion sculpturing pattern could provide useful characters for taxonomic and phylogenetic studies. In the Americas, morphological information of the egg exochorion obtained through scanning electron microscopy has become a complementary tool for taxonomic classification of sand fly species. The aim of this study was to examine and describe the exochorion pattern of eggs obtained from the abdomen of gravid wild females of 10 sand fly species collected in different areas of Mexico. We describe the chorionic pattern of 10 sand fly species collected during the period 1997–2023, which was classified as (1) polygonal, (2) connected and unconnected parallel ridges, (3) verrucose, (4) volcano-like and (5) disperse, being the polygonal pattern the most common among several species of the genera Dampfomyia, Micropygomia and Lutzomyia. This study describes the exochorion pattern of eggs directly obtained from the abdomen of preserved female specimens, supporting that extraction of eggs directly from an abdomen of a collection specimen might be a viable alternative to gather information of taxonomic value. We describe the eggshell of Bichromomyia olmeca olmeca, Dampfomyia deleoni, Micropygomyia cayennensis, Micropygomyia chiapanensis, Micropygomyia vindicator, Micropygomyia durani, Lutzomyia cruciata, Psathyromyia maya, Psathyromyia texana and Trichopygomyia triramula. We detected differences with respect to previous descriptions of Micropygomyia chiapanensis, Lutzomyia cruciata, and Psathyromyia texana, providing new reference information.