title: [A study of parasitic trematodes of Littorina saxatilis and their impact on this mollusc (author's transl)].
abstract: A monthly study of populations of Littorina saxatilis (mollusc, gasteropod) very strongly parasited has allowed to establish relations between the said mollusc and some parasite trematodes which live in it. A selection of animals was done in two stations of the Roscoff region (Finistere). A total of more than 1.000 individuals have been examined in each station. Eleven species of cercairs have been spotted. It has appeared that the Microphallus similis was the most represented: 79,86% of the total. This rate of parasitism does not change much throughout the year. The populations of molluscs strongly parasited by Microphallus similis show an important castration. A double association of cercairs remains rare but is yet possible. It appears that aged individuals are the most parasited. It seems that there would be a growth of parasites more important in females than in males.
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D008297:Male; D008974:Mollusca / Q000469:parasitology*; D012737:Sex Factors; D014200:Trematoda / Q000254:growth & development*
vernacular_title: Etude des trématodes parasites de Littorina saxatilis (Olivi) et de leurs effets sur cet hôte