Host Range and Host Specificity of an Ant-Pathogenic Gregarine Parasite, Mattesia geminata (Neogregarinida: Lipotrophidae)

Abstract

The neogregarine Mattesia geminata JOUVENAZ & ANTHONY 1979, originally described as an endoparasite of Solenopsis geminata (Fabricius 1804) (Formicidae: Myrmicinae) in Florida, had been found in 2 Leptothorax Mayr 1855 species (Myrmicinae) in Montana [BUSCHINGER et al 1995]. Rearing of the parasite was possible in 2 related European Leptothorax species. A range of Formicoxenini, Myrmicini and Solenopsidini including Monomorium pharaonis (Linnaeus 1758) (all Myrmicinae) could be infected, whereas other Myrmicinae and a Dolichoderinae species were not susceptible to Mattesia geminata. Though a careful study of its life cycle [KLEESPIES et al 1997] did not reveal any appreciable morphological differences between the material here investigated and that of JOUVENAZ & ANTHONY [1979], it was not possible to transfer the parasite to Solenopsis invicta Buren 1972 and Sxyloni McCook 1879, close relatives of the original host, S geminata. Perhaps physiologically different strains are involved. Infestation of Monomorium pharaonis was successful and numerous workers died, but the use of M geminata for biological control of these pest ants seems not feasible. Even when fed exclusively with infectious ant brood over weeks, the M pharaonis colonies were still thriving and growing. Another pest ant, Wasmannia auropunctata (Roger 1863) (Myrmicinae), was not susceptible to M geminata. The host range of the strain of M geminata here studied is evidently restricted to the tribe Formicoxenini with particular preference of the subgenus Leptothorax and some closely related social parasites (Harpagoxenus, Doronomyrmex), other subgenera (Myrafant M R Smith 1950, Temnothorax Mayr 1861) being less susceptible, and to a few other Myrmicinae of the tribes Myrmicini (Myrmica rubra) and Solenopsidini (Monomorium pharaonis).