Integrative taxonomy sheds light on the gregarine specificity of crickets

The range of hosts in which a pathogen species can live (host specificity) is influenced by both shared phylogenetic history and shared ecological traits of the prospective hosts. Unfortunately, for many host-pathogen systems, the degree of host specificity is seldomly understood, as is the case of gregarine parasites. Gregarines are poorly understood apicomplexans related to parasites responsible of causing infamous diseases such as malaria. Gregarines infect a wide set of marine and terrestrial invertebrate phyla including arthropods, and they are thought to have coevolved with their hosts. Many of the reports of gregarines, however, show that a single species can infect several distantly related host species, though this pattern is likely the result of misidentifications product of the exclusive use of morphology for its identifications.
In the present work we emphasize that the use of both morphological and genetic data is necessary to delineate gregarine species that are found in three species of distantly related crickets (Acheta domesticus, Gryllodes sigillatus and Gryllus sp.), whose has been previously reported to be infected by the same gregarine species, Leidyana gryllorum. The use of an integrative taxonomy approach on gregarines will shed light on the host specificity of the gregarine-insect system and will help to address further ecological and evolutionary questions in the system.