Summary: 1. Tannins are one of the most studied groups of plant secondary metabolites in research related to chemical ecology. They are traditionally thought to form an important factor of plant defence against herbivorous insects. 2. For a long time, tannins’ anti‐herbivore activity was thought to derive from their protein precipitation capacity that rendered plant tissues non‐nutritious and unpalatable for herbivores. Recent evidence suggests that tannin activity cannot be explained quite this simply, as tannin oxidation should also be taken into account as a defence mechanism for plants. 3. Tannins show very high variability in their structures with several hundred unique molecules detected in plants. These molecules are unevenly distributed in the plant kingdom and only very seldom—if ever—do two plant species share the same tannin pool. In many cases tannin composition varies even within organs of the same plant species and individual. Still, the overall tannin composition of many plant species is as of yet unknown. 4. Chemical ecology of tannins is challenging due to its multi‐disciplinary nature. To facilitate research on tannins, we must provide ecologists and chemists with methodological and collaborative alternatives that enable the true and holistic investigation of all important questions that may arise from the field. So far this has not been possible with the tannin oxidation hypothesis, since simple and widely usable methods have not been available. 5. The aim of this review is to give a clear but detailed view of the chemical ecology of tannins and the methodology used to study them. In addition, we introduce a new method to estimate the oxidative activity of all types of tannins and other phenolics that might cause oxidative stress to herbivores. Hopefully our arguments and method will lead to clear changes in the approaches we take to tannins and their exciting biological activities, and we will witness a new era of flourishing and productive research in the chemical ecology of tannins.

The Martini 3 force field is a full reparametrization of the Martini coarse-grained model for biomolecular simulations. Due to the improved interaction balance, it allows for a more accurate description of condensed phase systems. In the present work, we develop a consistent strategy to parametrize carbohydrate molecules accurately within the framework of Martini 3. In particular, we develop a canonical mapping scheme which decomposes arbitrarily large carbohydrates into a limited number of fragments. Bead types for these fragments have been assigned by matching physicochemical properties of mono- and disaccharides. In addition, guidelines for assigning bonds, angles, and dihedrals were developed. These guidelines enable a more accurate description of carbohydrate conformations than in the Martini 2 force field. We show that models obtained with this approach are able to accurately reproduce osmotic pressures of carbohydrate water solutions. Furthermore, we provide evidence that the model differentiates correctly the solubility of the polyglucoses dextran (water-soluble) and cellulose (water insoluble but soluble in ionic liquids). Finally, we demonstrate that the new building blocks can be applied to glycolipids. We show they are able to reproduce membrane properties and induce binding of peripheral membrane proteins. These test cases demonstrate the validity and transferability of our approach.