Demonstrating limitations of area-restricted search as a foraging mechanism

Foragers often rely on simple behavioral rules that translate local environmental cues into movement decisions. One of the most widespread rules is area-restricted search (ARS), in which movement becomes less directional following resource encounters. ARS is generally considered effective for exploiting clustered resources, yet recent conceptual work suggests it may also generate context-dependent failure modes that have rarely been tested within a unified spatial framework. Here, I use a spatially explicit individual-based simulation model to examine whether such failures can emerge directly from the operation of ARS. I compare ARS with alternative search modes that maintain constant directionality and focus on three potential failures: self-generated spatial bias arising from uneven resource depletion, over-reinforcement leading to excessive local search when encounters become uninformative, and increased variability in foraging success among individuals. The simulations show that ARS can generate apparent spatial clustering of prey even when resources are initially randomly distributed, and it becomes less efficient when isolated encounters trigger unproductive local search during depletion. ARS also increases variability in foraging success relative to more directional movement. However, similar patterns emerge under continuous movement with high tortuosity, indicating that these outcomes are not unique to ARS but arise more generally from tortuous movement. Despite these limitations, ARS remains effective in clustered environments. These results clarify when encounter-based search remains adaptive and when its performance breaks down, highlighting the importance of the informational value of encounters and the degree of movement tortuosity during local search.