The three hosts of the Ligula intestinalis (Cestoda) life cycle in Lavernose-Lacasse gravel pit, France

The life cycle of Ligula intestinalis, a pseudophyllidean cestode, was studied in a South-Western French gravel pit. Copepods, fish and piscivorous birds, constitute the hosts necessary for complete parasite development. In order to determine the actual species likely to be responsible for the very high level of parasitism observed, a two-year study was carried out. Our results show that the copepod Eudiaptomus gracilis, the roach (Rutilus rutilus) and the great crested grebe (Podiceps cristatus) were the most favourable hosts for continuation of the parasite life cycle. The study shows how alterations exerted by infective larval stages of L. intestinalis affect the population dynamics of roach.