How epidemiological patterns shift across populations in an exotic lizard.

Several factors influence the dynamics and structure of parasite communities. Our goal was to investigate how the community composition, prevalence and abundance of parasites change across seven populations of the exotic lizard Hemidactylus mabouia in Northeast Brazil, and to describe ontogenetic and sex variations. We found differences in the composition of component communities and patterns of infection according to the host body size across the lizard populations. We did not find any variation between the sexes regarding epidemiological patterns, which can probably be explained by the similar diet and habitat use of male and female H. mabouia. An unusually high abundance and prevalence of trematodes infecting this host lizard was apparent when we compared other native lizard hosts, and we suggest that local environmental conditions might be advantageous to the development and life cycle of these parasites due to the abundance of all the intermediate and definitive hosts.

Levels of helminth infection in the flat lizard Tropidurus semitaeniatus from north-eastern Brazil.

Parasites represent a great, unknown component of animal biodiversity. Recent efforts have begun to uncover patterns of infection by helminth parasites in several Neotropical lizards. The present study reports, for the first time, levels of helminth infection in a population of the flat lizard Tropidurus semitaeniatus. One hundred and thirty-nine lizards were examined and evidence of five intestinal helminth species was found, comprising four species of nematodes, one species of cestode and an unidentified encysted larval nematode. The most frequently occurring species was the intestinal nematode Parapharyngodon alvarengai, which did not exhibit differences in prevalence and intensity of infection relative to host sex or age/body size. Furthermore, helminth species richness was not related to host body size.