Figure 4.21 Risk-sensitive foraging. The sensitivity of young creek chubs (Semotilus atromaculatus) to food density and predators was tested in artificial streams. All streams had one side that contained one predatory adult creek chub and a low density of food (0.17 worms/cm2). (a) When the right end of the stream contained two predators and the same low density of food, the young chubs moved to the left side. (b) When the right end contained two predators and a medium food density (0.17 worms/cm2), the young chubs still moved to the left side. (c) Only when the side with two predators contained either a high food density (0.50 worms/cm2) or (d) very high food density (1.0 worms/cm2) did the young chubs move to the right side of the stream.
After J. F. Gilliam and D. F. Fraser, Habitat selection under predation hazard: Test of a model with foraging minnows, Ecology 68 (1987): 1856–1862.