HERITABLE NON-SUSCEPTIBILITY IN AN ALLOPATRIC HOST-PARASITE SYSTEM - BIOMPHALARIA-GLABRATA (MOLLUSCA) ECHINOSTOMA-CAPRONI (PLATYHELMINTH DIGENEA)

We studied the heritability of adult nonsusceptibility/susceptibility in an allopatric host-parasite system, Biomphalaria glabrata (Brazil)- Echinostoma caproni (Egypt). In this system, the fitness of the infect ed host is substantially reduced because of castration. Mean frequenci es of susceptibility among progeny of individual susceptible or nonsus ceptible parents were compared, and heritabilities of susceptibility a nd nonsusceptibility were calculated under a quantitative genetic mode l. A Monte-Carlo simulation was used to assess the significance of the heritability estimates under the hypothesis of normal standard deviat ion. The results showed high heritability of both nonsusceptibility (0 .56) and susceptibility (0.91).