The main goal of this study was to evaluate the relative influence of season, year of study, host body size, and host sex on abundance of helminth species parasitic in the frog Scinax nasicus. A total of 273 frogs was collected between December 2004 and November 2006 over all seasons in Corrientes City, Province of Corrientes, Argentina. Helminth community included 21 taxa, and was dominated particularly by larval trematodes. Infected frogs harboured a maximum of 7 species. Host sex and season played no significant effect in determining infracommunity parasite species abundance. Similarly, species richness was similar for both host sexes, and across time (year and season). However, occurrence of the parasites Opisthogonimus sp. 2 and Travtrema aff. stenocotyle greatly varied over time. Host body size was the main factor for determining infrapopulation structure of Centrorhynchus sp. Species richness was significantly and positively correlated with host body size. Strong associations were observed mainly between metacercariae of some species. The transmission strategies of parasites suggest that this hylid acquires infections by ingestion of infective larvae and through direct contact with larval parasites from aquatic and terrestrial habitats.
KEY WORDS: Helminth community · Season · Study period · Host body size · Host sex · Scinax nasicus
Resale or republication not permitted without written consent of the publisherDis Aquat Org 93: [71][72][73][74][75][76][77][78][79][80][81][82] 2010 (Combes 1972), and can also be a strong determinant of differences in parasite occurrences (Gillilland & Muzzall 1999, Bolek & Coggins 2001. In addition, sexual dimorphism can also influence parasite intensity or species richness (McAlpine 1997); the larger sex might be more infected because greater host body size provides more surface area for colonization by parasites, i.e. greater probability of skin penetration by cercariae and larval nematodes. Several studies of parasite richness in relation to host body size support this concept (Dogiel 1964, Price 1980, Bell & Burt 1991, Gregory et al. 1996.Studies of the influence of biotic factors and external environment on the structure of helminth parasite communities in amphibians have provided important information, showing that anthropogenic perturbations, such as watershed or landscape alterations, can have simultaneous negative and positive effects on distribution, and number of helminth parasite species in infracommunities (Hamann et al. 2006a, McKenzie 2007, King et al. 2008, Marcogliese et al. 2009). Similarly, habitat use (e.g. aquatic, arboreal, terrestrial), relative vagility, feeding preference in terms of foraging behaviour, range of prey species, and host size are key factors determining parasite species richness (Aho 1990, McAlpine 1997, Kehr et al. 2000, Muzzall et al. 2001, Bolek & Coggins 2003, Hamann et al. 2006b, Yoder & Coggins 2007.Additionally, the effect of season on the parasite recruitment period, and the breeding season of the definitive host...