Ectoparasitos e hemoparasitos de pinguins (Pygoscelis spp.) e skuas (Stercorarius maccormicki) nas ilhas Shetland do Sul, Antártica

Abstract

Parasites can act as key species in the maintenance of diversity, being the "hostparasite" relationships excellent models for analysis of evolutionary and ecological dynamics. Ectoparasites occur in all regions of the planet, while hemoparasites are limited by the distribution of vectors. At South Shetland archipelago, Antarctica, where there is little knowledge about parasites, there are only five recorded species, including the Ixodes uriae tick, which is associated with the transmission of pathogens in other regions where it occurs. Among the 40 species of birds that occur in Antarctica, there are the territorialist south polar skua (Stercorarius maccormicki), which migrates for long distances, and three species of Pygoscelis penguins (P. adeliae, P. antarctica and P. papua), which are colonial birds. In this context, the present thesis consists of three chapters, including a review on ectoparasites that occur in penguins (Sphenicidae) and skuas (Stercorariidae) families, and the relation of parasite richness with dispersion, population size and body size of hosts (chapter 1); an investigation of the ectoparasites of Pygoscelis penguins and skua S. maccormicki in the South Shetland archipelago, and the relationship between the prevalence and richness of parasites with intraspecific and interspecific parameters (chapter 2); and the investigation of Babesia spp. and Rickettsia spp. in the four species of birds studied and in ticks I. uriae, in addition to hemoparasite screening on blood smear slides (chapter 3). In chapter 1, only the richness of chewing lice in Sphenicidae was related to host body size, population size and dispersal of penguins species. In chapter 2, the only ectoparasite recorded in penguins was I. uriae. For S. maccormicki, two species of feather mites (Alloptes (Conuralloptes) catharacti and Zachvatkinia stercorarii) and two species of chewing lice (Haffneria grandis and Saemundssonia (Saemundssonia) euryrhyncha) were found. The prevalence of two ectoparasites varied intraspecifically between the sexes in S. maccormicki. Skuas with smaller beaks appear to be more efficient at the elimination of larger-sized parasites (H. grandis), which was also directly related to the body size of skuas. The ectoparasites found in skuas do not seem to influence the weight of the hosts. In chapter 3, we recorded the presence of Babesia spp. for the three species of penguins and in I. uriae, indicating that this may be the potential transmitter of Babesia spp. We recorded at the first time Leucocytozoon spp. in Antarctica, including the first records for the four species of birds studied. The presence of this haemosporidia, transmitted mainly by simulids, alerts to a possible introduction of these insects in the region. Our results show that the distribution of ectoparasites depends on several factors, and that the knowledge of the biological aspects of the host is important to understand its patterns in a population or region, and are still scarce, especially in relation to skuas and Antarctica. At the same time, the discovery of new hosts for Babesia spp., as well as the first record of Leucocytozoon spp. in Antarctica, highlights the importance of the development of vector and hemoparasite research in this continent, which can be a tool of health monitoring in this region.