Supervisors: ddr hab. Łukasz Michalczyk, prof. UJ (l.michalczyk@uj.edu.pl)

Institute of Zoology and Biomedical Research

Background information:

Despite an increasing interest in studying tardigrades, our understanding of their ecological preferences is extremely limited. This is mostly due to the fact that the bulk of our knowledge on tardigrades comes from fragmentary, opportunistic sampling rather than from large-scale, systematic research expeditions and, even more rarely, from replicated sampling of the same communities over extended periods of time. Moreover, the scarce literature data on tardigrade ecology are based solely on classical taxonomy, which we now know can be extremely inaccurate in determining micrometazoan species diversity, rendering ecological inference unreliable. Importantly, without pinpointing the factors that determine microhabitat preferences of tardigrades, our understanding of the biology and evolution of this phylum will not be possible. This project offers an opportunity not only to fill this considerable knowledge gap but also to test a hypothesis on the co-evolution of tardigrades and cryptogams, as well as to increase sampling efficiency by limiting the number of target cryptogam species.

The main question to be addressed in the project:

The primary objective of this project is to determine abiotic and biotic factors shaping communities of cryptogam-dwelling tardigrades. Moreover, the data will allow for testing a hypothesis that the evolutionary history of tardigrade species, which exhibit clear habitat preferences, should overlap with the phylogeny of the inhabited cryptogams.

Information on the methods/description of work:

Samples will be collected from locations along altitude gradients to provide variation in climate variables. In addition to temperature and sun exposure, cryptogams will be analysed for their physicochemical properties, such as pH, desiccation rate, and compaction (which are all predicted to affect tardigrade survival and reproductive success). Moreover, cryptogam habitats will be controlled for the composition of the cohabitant microfauna which may affect tardigrade community (e.g., via predation or competition). All organisms (tardigrades, cryptogams, and other micrometazoans) will be barcoded (via NGS) to obtain MOTUs (and species identifications wherever possible).

Additional information (e.g Special requirements from the student):

The project involves both intense fieldwork and laboratory work. Thus, apart from an interest in microfauna, ecology, and evolution, experience in fieldwork and a driving licence are required.

References:

[1] Guidetti R. et al. (2024) Tardigrade diversity and community composition across Norwegian boreal forests. Zoological Journal of the Linnean Society, 200(1): 156–171. [https://doi.org/10.1093/zoolinnean/zlad136]

[2] Guil N. & Sanchez-Moreno S. (2013) Fine-scale patterns in micrometazoans: tardigrade diversity, community composition and trophic dynamics in leaf litter. Systematics and Biodiversity, 11(2): 181–193. [https://doi.org/10.1080/14772000.2013.798370]