Cross-transplantations of Omphiscola glabra between two French departments (Haute-Vienne and Indre) were carried out to study snail settlement in these new sites during six years and to determine if this snail species was well adapted to its local parasites (Fasciola hepatica and Paramphistomum daubneyi). Local snails placed in new sites for each department were used as controls. In Indre furrows, the number of adults per population and the area of each habitat peaked on the third year post-introduction. Similar findings were also noted in the Haute-Vienne furrows occupied by local snails but peaks were only observed on the fourth year. In contrast, in Haute-Vienne sites populated by introduced snails, there was a progressive decrease in snail abundance and habitat area from the second year. The local O. glabra transplanted in Haute-Vienne kept their same degree de susceptibility to F. hepatica and P. daubneyi, thus demonstrating a good adaptation of these snails to their parasites. In other groups of transplanted snails, the first natural infections were only noted from the second or third year post-introduction and their prevalence progressively increased over time. Local adaptation of these latter snails to parasites would be more progressive in time and would stretch over several snail generations.

Field investigations on 12 populations of Omphiscola glabra were carried out in central France over a 5-year period to determine the ability of the species to aestivate in its habitats when summer drying occurred. In the department of Haute-Vienne, spring-born snails aestivated with their apertures applied to the surface of a substratum and most of them were located on the banks of ditches. With the return of wet conditions, the survival of these snails was low. In the department of Indre, most springborn snails aestivated by burrowing into the marl and were distributed over the whole surface area of their habitats. Higher survivals were noted for these O. glabra after aestivation. Despite a significant difference in the frequencies of buried lymnaeids, the position of snails with a natural infection with F. hepatica in their dried habitats was similar to that found for uninfected ones. The variations found in the aestivation of O. glabra might be explained by the dominant substratum (granite gravel and scarce mud in Haute-Vienne, or a thick layer of marl in Indre) and the plant cover on ditch bottoms.