Seasonal dynamics of infection of moor frog by nematodes Rhabdias bufonis from flood-land landscapes of Irtysh river

Abstract

The exploration on seasonal and age dynamics of indicators of infection of moor frog (Rana arvalis) by lung nematodes Rhabdias bufonis in the flood-land landscapes of Irtysh river from 2005 till 2012 years was conducted. Every-year decreasing of indicators of frogs’ infection by R.bufonis caused by the mass metamorphoses of young first-year frogs which may be infected by nematodes only on the land was registered. Probably R.bufonis forming 2 generations of adult worms during the snowless period, in favour of which 2 worms’ quantity risings – in spring and in autumn –testify. Nematodes spend a winter in the hosts so as to be saved of their infection elements in winter and in the period of spring floods.The decreasing of extensity of infection and abundance index of R.bufonis in the several years may be caused the decreasing of frogs’ quantity (connected with the drought of landscape with short-time or absent floods) and also the competition interactions with the lung trematode Haplometra cylindracea, whose quantity increased from 2007 till 2009 years. Besides the trematode in the first year and one-year-old frogs, and the nematode – in the large adult frogs with high intensity of infection usually parasitized.