A study on the distribution of Bothriocephalus andresi (Cestoda, Pseudophyllidea) in Citharus linguatula.

The distribution of Bothriocephalus andresi (Porta, 1911) in a population of Citharus linguatula (L.) caught off the Tuscan coasts was studied for one year. The negative binomial model proved useful for analysing the distribution of the parasite (B. andresi) in the host population. The ability of the parasite to adjust not only to its own environment but also to that of its host was clear, as it may be evinced from the greater amount of eggs and, hence, of larvae noticed in the period when there was abundance of plankton (high number of intermediate hosts). The balance achieved between host and parasite populations was also evident, and the modulation of the intensity of the infestation was such that it may be imputed to a greater immune response in the host.