The ecological analysis of the microhemipopulations of trematode parthenites: an experience

The paper analyzes the population structure of parasitic flatworms of the Himasthla larina species (Trematoda: Echinostomatidae). Abundance and size structure of their population directly relate to the size and weight of their first intermediate hosts, mollusks of the genus Littorina. When the invasion intensity is insignificant, growth of the size of parasitic organisms occurs simultaneously with the increase in their abundance regardless of the weight and size of the mollusk. If the weight and size of the host increase, the size of flatworms can grow only simultaneously with an increase of the host's weight. Further on inverse relationship between the size and abundance of parasites is observed. As a result of this study we may conclude that the formation of populations of trematode parthenites is subject to the same laws as the formation of populations of free-living organisms.