Gastro-intestinal helminths in the red-bellied squirrel introduced in Argentina: accidentals acquisitions and lack specific parasites

GOZZI, ANA CECILIA; GUICHON, MARIA LAURA; BENITEZ, VERONICA VICTORIA; TROYELLI, ADRIAN

HYSTRIX

ASSOC TERIOLOGICA ITAL

Año: 2014 vol. 25 p. 97 - 102

0394-1914

Introduced species may lose their natural parasites when invading a new habitat, may acquire new, local parasites or may introduce parasites form their native range. We studied the gastro-intestinal helminth fauna associated with the red-bellied squirrel Callosciurus erythreus (Pallas,1778) introduced in Argentina to evaluate its role as a host of either specific or acquired parasites in two invasion foci. We analyzed entire digestive tracts of 72 red-bellied squirrels captured in the main invasion focus (Lujan, province of Buenos Aires) between February and May 2011, and in a secondary focus (Cañada de Gomez, province of Santa Fe) in December 2008. We only found two nematode specimens: an adult male  belonging to the genus Pterygodermatites (Paucipectines) Quentin, 1969 and another adult male belonging to the genus Stilestrongylus (Freitas, Lent and Almeida, 1973). None of these genera were previously listed for the red-bellied squirrel in introduced areas , but a species of the genus Pterigodermatites was previously reported for this squirrel in its native habitat. These results indicate that, to date, the red-bellied squirrel in Argentina is accidentally parasited by nematodes acquired in its new enviroment and has no especific gastro-intestinal helminths. This could be related with a "founder effect" and/or the lack of sciurid rodents that prevent the red-bellied squirrel to be colonized by pre-adapted helminth taxa. Other factors that may play a role are the small number of mammals with arboreal habits and some ""encounter barriers" in the new environment that prevent the acqquisition of hleminths with a wide host spectrum.