Sand fly gregarines: their molecular characterization and host-parasite interactions

Gregarines (Apicomplexa: Gregarinasina) are monoxenous parasites of invertebrates. Those found in sand flies (Diptera: Psychodidae) and mosquitoes (Diptera: Culicidae) used to be considered a single eugregarine genus Ascogregarina. Our phylogenetic analyses of the gregarine SSU rDNA, including newly obtained sequences of three species from sand flies, showed that mosquito and sand fly gregarines are closely related to neogregarines, and most importantly, they form two disparate monophyletic groups. Based on these molecular features, accompanied by biological differences, we established a new genus Psychodiella for the gregarines from sand flies, reserving the genus Ascogregarina for the mosquito gregarines. In the new genus, two new species Psychodiella sergenti from Phlebotomus sergenti and Psychodiella tobbi from Phlebotomus tobbi were described. They differ in the life cycles (sexual development of Ps. sergenti is triggered by a blood meal intake) and morphology of their life stages, mainly oocysts. The susceptibility of five sand fly species to both gregarines showed their strict host specificity, as they were able to fully develop and complete the life cycle only in their natural hosts. The life cycle of Ps. sergenti was studied in detail using various microscopical methods. Oocysts are..