Spatio-temporal variations in larval digenean assemblages of Heleobia parchappii (Mollusca: Cochliopidae) inhabiting four human-impacted streams

PARIETTI, M.; MERLO, M.J.; ETCHEGOIN, J.A.

J. HELMINTHOL.

Cambridge University Press

Año: 2020 vol. 94

0022-149X

In the last years, a growing number of studies have focused on the search for biological indicators of human impact in freshwater environments. Given their susceptibility to differenttypes of impact, larval digeneans have been considered as useful tools for the study of temporal variations in parasite communities. However, few studies have been carried out inlotic environments. For that reason, the spatio-temporal variations of the larval digeneanassemblages parasitizing the gastropod Heleobia parchappii were analysed in four humanimpacted streams, located on the coast of Argentina. In total, 4800 specimens of H. parchappiiwere collected seasonally, and 12 digenean species belonging to eight families were registered.Three of the streams showed similar species presence but, during spring and summer, thestreams located within the city presented lower species presence than the streams locatedin the urban periphery. By contrast, the spatial prevalence values evidenced a higher variationbetween the environments. Streams located in the urban periphery showed higher prevalencevalues throughout the year, compared to those calculated for streams located within the city.The spatio-temporal variations of larval digenean assemblages parasitizing H. parchappii seemto be mainly influenced by the diversity and vagility of definitive hosts, the types of digeneanlife cycles and habitat characteristics. However, environmental disturbances derived fromanthropogenic activities are highlighted as the probable main factors that may affect the composition and dynamic of these parasite assemblages.