Major questions:

1) How does the insecticide Bti affect the emergence and subsidy quality of non-target prey organisms, such as Chironomids?

2) Do these effects also affect the food quality or feeding behaviour of riparian insectivore arthropods that prey on Chironomids?

Approach: Aquatic and terrestrial food webs are linked by the emergence of merolimnic insects, which serve as prey for riparian insectivore predators. Stressors such as drought or chemical pollution (including Bti application) can affect the magnitude, temporal dynamics as well as the quality of this subsidy with potential consequences for riparian insectivore arthropods, such as spiders. Building on the knowledge of the first cohort of the SystemLink project, this project will take advantage of laboratory and semi field (focus on enclosures) experiments. Thereby, the project targets the physiology, reproduction and predation of spiders on aquatic as well as terrestrial prey involving besides fatty and amino acid, also stable isotope analyses. Synergisms with parallel projects supervised by Manfrin and Schirmel are expected particularly for the envisaged semi-field experiments. All in all, this project will contribute to a more comprehensive understanding of the trophic implications (i.e., top-down) in recipient riparian food webs induced by subsidy from stressed aquatic ecosystems.