Macroparasites in Antarctic penguins

Parasitism is a highly common mode of living in animals being parasite species very abundant. Parasites affect in a different ways the host life through subtle effects to more dramatic effects causing population crashes and then regulating host populations. Antarctica and the Southern Ocean wildlife show also parasites although the published information is very scarce. This is even in the case of the most studied group of Antarctic seabirds, the penguins. In this chapter, we analyze the published information about the presence, epidemiology, life cycles, and effects of macroparasites, helminths, and ectoparasites in Antarctic penguins. Most of the publications only give information about the presence/absence of parasites, and very few give data about epidemiology such as prevalence or intensity of parasitization. The information about intermediate host is almost absent, and parasite effects have been addressed very few times. Moreover, the information is based on few areas, and there is not any long-term data set which makes difficult a broad understanding of the impact of parasites in the ecology of penguins. Nevertheless, the little information allows extracting some conclusions. First, the diversity of parasite species is very low which can be explained by the narrow diet spectrum and the harsh conditions. Second, helminths occur at higher prevalence than ectoparasites. In general, a trend of decreased macroparasite prevalence towards more southerly locations can be identified, although the small number of studies precludes a robust conclusion. Third, general parasite effects have been reported causing tissue damage, changes in immune parameters, reduction in body mass, reduction of breeding success, and transmission of diseases, this later in the case of ticks. Finally, it is expected that climate change will affect host-parasite interaction in penguins due to changes in the parasite distribution, host exposure, or resistance, but a higher number of studies with good quality data at long term are needed to confirm the expectations and a deeper understanding of the ecological aspects of parasites such as life cycle, epidemiology, and health impacts in the penguins.