Emergent aquatic insects represent a key vector for aquatic-based nutrients to penetrate adjacent terrestrial food webs. Long-chain polyunsaturated fatty acids (LC-PUFA) have been a recent interest when quantifying the cross-ecosystem transfer of dietary nutrients. Aquatic insects contain higher LC-PUFA, such as eicosapentaenoic acid (EPA), arachidonic acid (ARA), and docosahexaenoic acid (DHA), than terrestrial insects. The importance of LC-PUFA has been demonstrated for several riparian predators (e.g., birds, bats, and spiders), thus the penetration of aquatic insects into terrestrial habitats strongly dictates the availability of these LC-PUFA in terrestrial food webs. We deployed Malaise/window hybrid traps at 8 different distances (ranging from 1 to 1000 m) from the lake shore in two different terrestrial habitats (i.e., forested and meadows) to estimate the terrestrial penetration of aquatic biomass and LC-PUFA (i.e., EPA, ARA, DHA). Terrestrial insect biomass generally did not differ with distance from the lake, but aquatic biomass decreased with distance from lake shore in both habitats at differing rates. Our dataset provides order-level aquatic and terrestrial insect abundance along a distance gradient and demonstrates that physiologically-important aquatic-derived LC-PUFA are only available for terrestrial predators within a few meters of a lakeshore, highlighting the importance of riparian zones for terrestrial food webs.

Primary Presenter: Tarn Preet Parmar, Brandenburgische Technische Universität Cottbus-Senftenberg (tarnpreet.parmar@gmail.com)

Authors:

Tarn Preet Parmar, Brandenburg University of Technology Cottbus–Senftenberg (Department of Aquatic Ecology) / University of Konstanz (Limnological Institute)   (tarnpreet.parmar@gmail.com)

Alina Kindinger, University of Konstanz (Limnological Institute)  ()

Margaux Mathieu-Resuge, University of Vienna (WasserCluster Lunz) / Université de Brest, CNRS, IRD / Ifremer, Laboratoire de Biologie Halieutique  ()

Cornelia Twining, University of Konstanz (Limnological Institute) / Max Planck Institute of Animal Behavior / Eawag (Department of Fish Ecology and Evolution)  ()

Jeremy Shipley, Eawag (Department of Fish Ecology and Evolution)  ()

Martin Kainz, University of Vienna (WasserCluster Lunz) / Danube University Krems (Department of Biomedical Research)  ()

Dominik Martin-Creuzburg, Brandenburg University of Technology Cottbus–Senftenberg (Department of Aquatic Ecology)  ()