Resumen

MUNOZ, GABRIELA; VALDEBENITO, VERÓNICA  y  GEORGE-NASCIMENTO, MARIO. Diet and metazoan parasite fauna of the thornfish Bovichthys chilensis Regan 1914 (Pisces: Bovichthydae) on the coast of central-south Chile: geographical and ontogenetic variations. Rev. chil. hist. nat. [online]. 2002, vol.75, n.4, pp. 661-671. ISSN 0716-078X.  doi: 10.4067/S0716-078X2002000400003.

Knowledge on what, how much, when and where hosts eat and live should help to understand the changes that occur in parasite communities because transmission of endoparasites is tightly linked to diet composition as well as ectoparasites are to the use that hosts make of the habitat. Thus, geographical and ontogenetic variations in diet and parasite fauna of the thornfish Bovichthys chilensis are described, and discussed taking into account the ontogenetic shifts in this host's niche. A total 122 individuals: 108 juveniles collected from the intertidal zone at four localities along the south-central coast of Chile (between 33º and 40º S), and 14 adults collected from the shallow subtidal at a fifth locality (36º S), were examined for food contents and parasite infracommunities. Food items were encountered in almost 70 % of fish examined with 25 prey items being recognized. Only one of the prey items was found in both juvenile and adult fish. The diet of juvenile fish consisted mainly of amphipods and while that of adults was mainly composed of crustacean decapods. Almost 40 % of fish examined harbored parasites with a total of 624 individuals and belonging to 16 taxa being identified, four of which were shared between juvenile and adult fish. Prevalence, total intensity, richness, and diversity of parasites was similarly low among juvenile fish sampled at four different localities, while significant differences in total prevalence, dietary and parasite infracommunity composition among localities were found. Absence of a clear relationship among juvenile fish between the composition of the diet and of infracommunities may be due to the fact that parasitoses are necessarily recent. Adult hosts had infracommunities with greater total prevalence, total intensity, taxonomic richness and diversity than juveniles sampled at a nearby locality. All these observations could be associated to ontogenetic shifts in diet and concomitant shifts in parasite fauna. Further studies are required, especially on geographical variations of the parasitism among adult thornfish to elucidate whether the host ontogenetic axis could be more important than the geographical in this species, when attempting to explain sources variations in the parasite fauna

Palabras clave : diet; parasites; host ontogeny; Bovichthys chilensis; Chile.