Seasonal maturation of Glypthelmins vitellinophilum (Trematoda: Digenea) in Lysapsus limellus (Anura: Pseudidae) from an argentinean subtropical permanent pond.

HAMANN, M. I.

BRAZILIAN JOURNAL OF BIOLOGY

Cubomultimídia publicações

Lugar: São Carlos; Año: 2006 vol. 60 p. 85 - 93

1519-6984

From December 1995 to November 2000, the seasonal maturation of Glypthelmins vitellinophilum Dobbin, 1958, in its definitive host, the frog Lysapsus limellus Cope, 1862, was studied in a subtropical permanent pond in the northeast of Argentina. The objectives of this study were: 1) to determine the infrapopulation dynamics of the parasite, analyzing the seasonal maturation cycle throughout the years, and, 2) to examine the relationship between intensity of trematode infection at different developmental stages (recruitment, growth and maturation) and the host´s body length. From 1,400 frogs examined over 60 months (5 years), 38% were found infected with G. vitellinophilum, and the intensity of infection was 1-15 trematodes per frog. Specimens of G. vitellinophilum were present in L. limellus throughout the years but did not show a pronounced seasonal cycle of maturation. Possible reasons for these results are discussed with reference to climatic fluctuations and biotic factors. The infective period of the parasite (stage I) occurred in summer, autumn and spring, coincidentally with the time of appearance of each frog cohort. These infections were found principally in small body sizes (classes 1 and 2) of L. limellus. Growth of worms (stage II and III) took place in different body sizes of frogs throughout the period of investigation. Gravid specimens of the parasite (stage IV) were generally registered in autumn, winter and spring, mainly in the larger body sizes of frogs. Trematode?s body length of stages I and IV was significantly and positively correlated with frog´s body length.