The site preferences of two digeneans, Asymphylodora kubanicum and Sphaerostoma bramae, in the intestine of the roach.

The digeneans Asymphylodora kubanicum and Sphaerostoma bramae showed distinct and different site preferences in the roach intestine, the majority of A. kubanicum being found in the first limb and the majority of S. bramae occurring in the second and third limbs. A. kubanicum excysts and establishes itself in the first limb and this is considered to be the basis of the observed distribution of the parasite in the host's intestine. The site preference of S. bramae is discussed in relation to the physiology of the parasite and the host and to possible competitive interactions with A. kubanicum.