Survey investigations in Michigan have revealed (a) that noxious or unpalatable compounds are widespread and diverse among shoreline emergents in families known for their terrestrial anti-insect compounds, (b) that rooted, floating macrophytes, especially several genera of lily pads (e.g., Nymphaea, Brasenia, Nuphar), contain high concentrations of phenolics in addition to alkaloids, and (c) that submersed macrophytes have greatly reduced levels of both phenolics and alkaloids, although certain compounds (e.g., ferulic acid, anthocyanins) are retained in modest concentrations. This past summer, we investigated whether anti-insect compounds were effective against aquatic invertebrates, and the relationship between phenolic and "allelopathy" bioassay results. Additionally, we explored the use of metabolic blockage techniques. The latter protocol has both basic and applied promise.