Silica Particles with Encapsulated DNA as trophic tracers

Ecological networks such as food webs are extremely complex and can provide important information about the robustness and productivity of an ecosystem. In most cases it is not feasible to observe trophic interactions between predators and prey directly and with the available methods it is difficult to quantify the connections between them. Here we show that submicron-sized Silica Particles (100 – 150 nm) with Encapsulated DNA (SPED) enable accurate food and organism labeling and quantification of specific animal-to-animal transfer over more than one trophic level. We found that SPED were readily transferable and quantifiable from the bottom to the top of a two-level food chain of arthropods. SPED were taken up in the gut system and remained persistent in an animal over several days. When uniquely labeled SPED were applied at predefined ratios we found that information about their relative abundance was reliably conserved after trophic level transfer and over time. SPED were also applie...