A total of 36 adult individuals of Leptodactylus latinasus were collected near the city of Corrientes, Province of Corrientes in Argentina. The main goals of this study were: (1) to determine the helminth parasite fauna of L. latinasus; (2) to determine the richness and diversity of parasites at the component and infracommunity levels; (3) to analyze the relationships between helminth, frog body size and sex; and (4) to identify and examine species affinity of helminth communities. The helminth component community of this frog's population consisted of 17 species. The predominant groups of parasites were the trematodes (adults: Glypthelmins repandum, Catadiscus inopinatus and Haematoloechus longiplexus; larvae: Travtrema aff. stenocotyle, Bursotrema aff. tetracotyloides, Styphlodora sp., unknown opisthogonimid species, Petasiger sp. and unknown strigeid species), followed by the nematodes (Cosmocerca podicipinus, C. parva, C. rara, C. cruzi, Schrankiana schranki and Aplectana hylambatis); other groups of parasites were represented by only one species (unknown larval cestode species and Centrorhynchus sp.). All parasite helminth species showed an aggregated pattern of distribution. The most infected organs were kidneys, small intestine, large intestine and pharyngeal zone. The host body size was important in determining the parasites abundance of G. repandum. At the level of component community G. repandum was the species with highest prevalence of infection and Bursotrema aff. tetracotyloides was the dominant species. Helminth species showed four significant pairs of covariation and two significant pairs of association in the infracommunities of Leptodactylus latinasus.

One hundred seventy-two frogs (Leptodactylus chaquensis) were collected from November 2002 to November 2003, in agricultural (n = 132) and nonagricultural (n = 40) areas. Both sites are near the city of Corrientes, Argentina. The main goals of this study were as follows: (1) to determine the helminth parasite community in agricultural and nonagricultural habitats; (2) to analyze the relationships between helminth parasites and site of infection, frog body size, and gender; (3) to identify and examine covariation and association of helminth communities; and (4) to determine the mean richness and diversity of parasite communities. The helminth compound community of this amphibian species consisted of 24 species: 19 in agricultural habitats and 18 in nonagricultural habitats. The mean richness, mean diversity, and evenness of helminths were significantly different between the habitats (P < 0.05). The body size of the host was the important factor in determining parasite richness. Both habitats exhibited differences in community ordination. The helminth species in the 2 habitats exhibited the same interspecific relationships, although differences were observed in the intensity of infection.

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...

Abstract:The main goals of this study were to determine the richness and diversity of helminth parasites of Rhinella fernandezae at the component and infracommunity levels and determine the ecological implications of different biotic and abiotic factors. Specimens were collected near the city of Corrientes, Corrientes Province, Argentina. Prevalence of infection was 94% in the specimens examined (n = 65). The helminth component community in R. fernandezae in this area was comprised a total of 22 species. Of all helminth species, only three (Catadiscus inopinatus, Cosmocerca podicipinus and C. parva) were dominant (importance value: I > 1.0) in the community. The most abundant species were B. tetracotyloides (d = 0.43) among the larvae and C. podicipinus (d = 0.09) among adult worms. At the infracommunity level, the mean individual species richness (2.28 ± 1.48) (mean ± SD) was no more than 3 helminth species per infected host; the diversity and equitability of helminths were 0.23 ± 0.21 and 0.48 ± 0.38, respectively. The host body size was the main factor in determining the parasite abundance. Species richness was significantly and positively correlated with host body size. The parasite helminth species predominantly showed an overdispersed pattern of distribution. Helminth species showed two negative and significant pairs of covariation and one significant pair of association (P < 0.05). R. fernandezae has a wide variety of parasites relating to the host microhabitat, mobility and feeding habits.

Ecological aspects of diet, reproduction, and parasitism of Pseudopaludicola boliviana (Anura, Leptodactylidae) from Corrientes, Argentina. The main objectives of this paper were to update the distribution range of Pseudopaludicola boliviana in Argentina, to determine its diet composition and the feeding patterns, to analyze some reproductive variables as mature ova count and diameter in relation to female snoutvent length, to describe the advertisement call for Argentinean populations, and to identify and to localize its helminth parasites. Eleven prey types were identified; dipterans were more important both in number (23.53%) and in volume (41.30%); other important preys were collembolans, arachnids and coleopterans. The trophic niche width was 7.15 and the standardized trophic niche value was 0.61. Ovarian complement (number of mature ova for female) ranged from 50 to 319 (mean 175.3 ± 86.12), while ovum diameter ranged from 0.2 to 0.4 mm (mean 0.27 ± 0.062). The nuptial call is composed by five notes. The dominant frequency ranged from 3.488 to 5.927 kHz; emphasized frequency fluctuated between 4.942 and 5.224 kHz. A total of 10 helminth species (larvae and adults) were found in 54 (96%) infected frogs. Helminths were represented by Trematoda (7 species), Cestoda (1), Nematoda (1), and Acanthocephala (1).