Sardine cycles, krill declines, and locust plagues: revisiting 'wasp-waist' food webs.

'Wasp-waist' systems are dominated by a mid trophic-level species that is thought to exert top-down control on its food and bottom-up control on its predators. Sardines, anchovy, and Antarctic krill are suggested examples, and here we use locusts to explore whether the wasp-waist concept also applies on land. These examples also display the traits of mobile aggregations and dietary diversity, which help to reduce the foraging footprint from their large, localised biomasses. This suggests that top-down control on their food operates at local aggregation scales and not at wider scales suggested by the original definition of wasp-waist. With this modification, the wasp-waist framework can cross-fertilise marine and terrestrial approaches, revealing how seemingly disparate but economically important systems operate.