Morfometría y fecundidad de Profilicollis bullocki Mateo, Córdova & Guzmán 1982 (Acanthocephala: Polymorphidae) en especies simpátricas de aves costeras de Chile

we describe and compare the variations in morphology and fecundity of profilicollis bullocki mateo, córdova & guzmán 1982 (acanthocephala: polymorphidae) adults collected from 4 alternative sympatric and definitive marine coastal bird host species (larus dominicanus lichtenstein 1823, larus pipixcan wagler 1831, podiceps occipitalis garnot 1826 and numenius phaeopus linné 1758), sampled at caleta lenga, chile (36o45' s, 73o10' w). results show that the specific identity of the host species is a relevant factor to explain morphometric and reproductive variations of p. bullocki. parasites in larus spp. attain larger body size than in the two other host species. in addition, fecundity increases with parasite body size. however, analysis on the residuals of the linear regression between fecundity and body size show that fecundity in l. dominicanus and in l. pipixcan are similar and both higher than in p. occipitalis. we suggest that estimates of host abundance along with abundance of parasites within each host species are needed to determine which is the best host for a parasite, as well as the reproductive performance of the parasite in each host species