Parasitic Rove Beetles

Staphylinidae, Staphylininae,

Amblyopinini.

Because ectoparasitism is a rare phenomenon among beetles, these few rove beetle species that live on rodents and marsupials are extraordinarily interesting (Machado-Allison and Barrera 1972, Seevers 1955). They exhibit a high degree of host specificity, and species have been found to be associated with a large variety of mammals. Numerous species in five genera occur mostly in mountainous areas from Central America throughout the Andes to southern Chile and Argentina and across the continent in southeastern Brazil (Ashe and Timm 1988). Many more species are thought to exist. (It is odd that outside Latin America, the tribe is represented only by one genus in Australia and Tasmania.)

All are fairly typical rove beetles in their dark brown color and general elongate form, showing no obvious structural adaptations for ectoparasitism (fig. 9.4c). Some have a flat, shovel-shaped head and heavy setae on the underside of the abdomen which may have some function as yet unknown, possibly one associated with parasitism. They are distinguished from relatives by a pair of conspicuous lobes projecting from the tip of the abdomen, each bearing large setae at the apex.

Adults attach firmly to mice and opossums, usually on the hindquarters or near the anus. They have been seen to bury their mandibles in the skin, although they do not feed on the host but are predators on the host's ectoparasites. Observations of the immatures are lacking.

Rodent host genera are mainly myo-morphs and hystricormorphs, including many peculiar South American types such as guinea pigs, chinchillas, pacas, and capybaras, although mice and rats in such genera as Cyemomys and Oryzomys are more usual. Marsupial hosts are all opossums in the genus Didelphis.

References

Ashe, J. H., and R. M. Timm. 1988. Chitambty. opinus piceus, a new genus and species of Amblyopinine (Coleoptera: Staphylinidae) from southern Chile, with a discussion of Amblyopinine generic relationships. Kans. F.ntomol. Soc. J. 61: 46-57. Machado-Allison, C. E., and A. Barrera. I 1972. Venezuelan Amblyopinini (lnsecta: Coleoptera: Staphylinidae). Brigham Young Univ. Sci. Bull. 17: 1-14. Seevers, C. H. 1955. A revision of the tribe Amblyopinini: Staphylinid beetles parasitic on mammals. Fieldiana Zool. 37: 211—264.

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