Paper with Ashkaan Fahimipour on food web assembly, is out in Ecology Letters. In this work, we allowed experimental mesocosms to be colonized and we repeatedly measured the food webs that formed in these habitats as they assembled. We then used techniques from food web analysis and information theory to study how these webs changed through time. We showed that food webs follow predictable trajectories as they develop and that the assembly process is strongly driven by the arrival rate of dispersers from outside habitats. Interestingly, webs develop a fast energy channel that forms early and remains fairly stable through assembly, and many highly unstable slow energy channels that form and break continually. This structure–stable fast channel, unstable slow channels–appeared over and over in our experimental webs, suggesting that it may be a vital structural feature of assembling food webs in nature.