Skip to main Communities My dashboard Log in Sign up Animal Ecology (Prof. Dr. Alexander Wacker), Zoological Institute & Museum, University of Greifswald Published February 12, 2026 | Version v1 Dataset Open When Timing Matters - Shedding light on mechanisms under-lying host-pathogen dynamics in freshwater Authors/Creators Wacker, Alexander (Contact person) 1 Show affiliations 1. Universität Greifswald Description When Timing Matters - Shedding light on mechanisms under-lying host-pathogen dynamics in freshwater Invertebrates possess an innate immune system that acts non-specifically against pathogens and is regulated by the circadian clock. We used a well-established host–parasite system, Daphnia magna and its parasite Pasteuria ramosa , to investigate day–night differences in susceptibility. In an infection experiment where hosts were exposed to spores either during day or night, we found slight increases in daytime infection. We demonstrate that Daphnia exhibits rhythmic expression of five immune genes, with a major peak around the transition from day to night and low expression during day likely explaining higher susceptibility during day. Higher daytime susceptibility may benefit Pasteuria , as Daphnia likely encounters surface sediments with spores during day due to diel vertical migration. Exposure to the clock-dependent hormone melatonin altered immune gene expression and increased susceptibility both day and night, probably by immune suppression from melatonin. Melatonin may influence the parasite by signaling spore maturation. The freshwater keystone species Daphnia may experience altered infection dynamics when circadian rhythms and melatonin signaling are disrupted by anthropogenic stressors, with potential consequences for population structure and food webs. Our results spotlight the mechanisms underlying infection risk in host-pathogen systems highlighting the importance of circadian regulation for disease dynamics in freshwater ecosystems . Files Files (38.1 kB) Name Size Download all When Timing Matters-Shedding light on mechanisms underlying host-pathogen dynamics in freshwater.xlsx md5:bf74c5d26a82ec8699899be867f8561c 38.1 kB Download Additional details Dates Updated 2026-02-16 Software Programming language R 60 Views 22 Downloads Show more details All versions This version Views Total views 60 60 Downloads Total downloads 22 22 Data volume Total data volume 906.5 kB 906.5 kB More info on how stats are collected.... Versions External resources Indexed in OpenAIRE Communities Details DOI DOI Badge DOI 10.5281/zenodo.18624706 Markdown [](https://doi.org/10.5281/zenodo.18624706) reStructuredText .. image:: https://zenodo.org/badge/DOI/10.5281/zenodo.18624706.svg :target: https://doi.org/10.5281/zenodo.18624706 HTML <a href="https://doi.org/10.5281/zenodo.18624706"><img src="https://zenodo.org/badge/DOI/10.5281/zenodo.18624706.svg" alt="DOI"></a> Image URL https://zenodo.org/badge/DOI/10.5281/zenodo.18624706.svg Target URL https://doi.org/10.5281/zenodo.18624706 Resource type Dataset Publisher Zenodo Rights License Creative Commons Attribution 4.0 International The Creative Commons Attribution license allows re-distribution and re-use of a licensed work on the condition that the creator is appropriately credited. Read more Citation Export Technical metadata Created April 16, 2026 Modified April 16, 2026 Jump up About About Policies Infrastructure Principles Projects Roadmap Contact Blog Blog Support Help FAQ Developers REST API OAI-PMH Contribute GitHub Donate Funded by Powered by CERN Data Centre & InvenioRDM Status Privacy policy Cookie policy Terms of Use This site uses cookies. Find out more on how we use cookies Accept all cookies Accept only essential cookies