Transmission strategies and environmental factors shaping communities of trematode larvae in freshwater snails

Petra KUNDID, MSc.

Disertační práce

Abstract:

This thesis examines the patterns of composition, structure, diversity and transmission of larval trematode communities in freshwater snail hosts from Europe. The research primarily focuses on small lymnaeid snails (Gastropoda) from man-made post-mining lakes in northern Bohemia, Czech Republic, and is complemented by samples from additional natural systems in Norway and Slovakia. By integrating long-term field sampling, experimental methods and molecular species identification, the study investigates trematode communities at multiple ecological and spatial levels. Community composition, infection parameters and temporal dynamics are analyzed in relation to abiotic and biotic environmental factors, host population structure and ecosystem characteristics. Molecular tools are applied to resolve hidden diversity and refine host-parasite associations, demonstrating that morphology-based identification alone substantially underestimates richness and community complexity. Beyond community-level patterns, the thesis explores transmission as a key component of parasite dynamics. Experimental studies on cercarial emergence of selected trematodes reveal species-specific temporal rhythms linked to environmental cues and host traits. Rare and highly specialized transmission strategies, including morphological and behavioral adaptations, are documented through comparative sampling across geographically distinct systems. The results demonstrate that trematode communities in freshwater snails are strongly structured by interacting environmental factors, including habitat type, successional stage and antropogenic influence, and transmission-related traits. By linking molecular diversity, community ecology and life-cycle biology, this thesis advances understanding of how parasite assemblages are structured and maintained in freshwater ecosystems. The thesis also demonstrates that transmission traits play an important role in shaping infection dynamics and parasite persistence. The findings highlight the ecological significance of snail-trematode systems as sensitive indicators of habitat condition and as dynamic components of aquatic food webs.

Abstract:

This thesis examines the patterns of composition, structure, diversity and transmission of larval trematode communities in freshwater snail hosts from Europe. The research primarily focuses on small lymnaeid snails (Gastropoda) from man-made post-mining lakes in northern Bohemia, Czech Republic, and is complemented by samples from additional natural systems in Norway and Slovakia. By integrating long-term field sampling, experimental methods and molecular species identification, the study investigates trematode communities at multiple ecological and spatial levels. Community composition, infection parameters and temporal dynamics are analyzed in relation to abiotic and biotic environmental factors, host population structure and ecosystem characteristics. Molecular tools are applied to resolve hidden diversity and refine host-parasite associations, demonstrating that morphology-based identification alone substantially underestimates richness and community complexity. Beyond community-level patterns, the thesis explores transmission as a key component of parasite dynamics. Experimental studies on cercarial emergence of selected trematodes reveal species-specific temporal rhythms linked to environmental cues and host traits. Rare and highly specialized transmission strategies, including morphological and behavioral adaptations, are documented through comparative sampling across geographically distinct systems. The results demonstrate that trematode communities in freshwater snails are strongly structured by interacting environmental factors, including habitat type, successional stage and antropogenic influence, and transmission-related traits. By linking molecular diversity, community ecology and life-cycle biology, this thesis advances understanding of how parasite assemblages are structured and maintained in freshwater ecosystems. The thesis also demonstrates that transmission traits play an important role in shaping infection dynamics and parasite persistence. The findings highlight the ecological significance of snail-trematode systems as sensitive indicators of habitat condition and as dynamic components of aquatic food webs.

Keywords

ecological parasitology, trematodes, snails, post-mining lakes, molecular, transmission, bioindicators

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 20. 2. 2026

Obhajoba závěrečné práce

• Obhajoba proběhla 11. 5. 2026
• Vedoucí: Mgr. Miroslava Soldánová, Ph.D.

JIHOČESKÁ UNIVERZITA V ČESKÝCH BUDĚJOVICÍCH

Přírodovědecká fakulta

Doktorský studijní program / obor:
Parasitology / Parasitology