Low flows are a major disturbance in streams and affect invertebrate community structure potentially through both abiotic and biotic processes. However, the relative importance of the different mechanisms in structuring low-flow affected communities is not well understood. Invertebrate responses to low flows are likely to depend on their life-history strategy and susceptibility to predation. Helen Warburton and Angus McIntosh investigated how the abundance of primary consumers and predatory invertebrates in streams changed when subject to low-flow disturbance. A mesocosm experiment was also conducted to determine how low flows changed predation pressure, and how invertebrates with different life histories (a hemimetabolous insect, the mayfly Deleatidium sp., and a holometabolous insect, the cased caddisfly Pycnocentrodes aeris) responded to these conditions. In sections of streams with low flows, the abundance of mayflies and caddisflies decreased, and the number of predators relative to prey increased. In the mesocosms, low-flow conditions initially increased the number of invertebrates emerging, but emergence was impeded with an extended period of low flow (see figure below).