Gastrointestinal parasites in rodent middens across the Atacama Desert of northern Chile

Deserts are unique ecosystems, characterized by extreme conditions and singular biodiversity. The Atacama Desert, South America, is one of the harshest environments on Earth. Rodent middens are valuable archives of desert ecosystems, offering insights into desert ecosystems worldwide. In the last years, rodent middens have been recognized as excellent sources of gastrointestinal parasites in dryland ecosystems. Parasites comprise a large portion of the world's biodiversity, and often play a crucial role in ecosystems. However, there is an overall dearth of knowledge of parasite ecological patterns and processes, especially from deserts. This study aims to investigate gastrointestinal parasite assemblages from current rodent middens across the Atacama Desert, and discuss their distribution at the regional scale. A wide diversity of gastrointestinal parasites was revealed through coproparasitological studies. Eighteen parasitic taxa or morphotypes belonging to Nematoda, Cestoda and Coccidia were identified, and were associated with three rodent families (Chinchillidae, Cricetidae and Octodontidae). Higher parasite richness and number of eggs/oocysts were found at lower-latitude and mid-altitude regions, aligning with the primary productivity patterns of the region. The adaptation of rodents and their parasites to extreme conditions highlights the intricate relationships between species and their environments. This study underscores the value of rodent middens as crucial archives for assessing parasite presence in extreme environments; and emphasizes the importance of considering latitudinal and altitudinal variations in understanding parasite community patterns.