Insects repeatedly encounter resources, hosts, hazards and landmarks whose value changes through time. Prior experience can therefore modify later movement, yet memory is commonly treated either as a cognitive trait or as a local behavioral mechanism without asking when its effects become ecologically consequential. This perspective uses ecological memory for retained information generated by an individual’s previous interaction with its environment that changes subsequent search, route use or site choice. The term does not imply one neural substrate, retention interval or adaptive effect. Evidence across bees, ants, parasitoid wasps, mosquitoes, butterflies and Drosophila shows that experience can recalibrate search, establish habitual routes, bias host or oviposition choice, and be updated or mislead behavior. Effects depend on receiver state, cue reliability, current goals and environmental structure. A proposed scaling architecture separates evidence-supported individual effects from population inference. Memory can contribute to redistribution only when behavioral effects are sufficiently persistent, prevalent and spatially directional; persistence additionally requires demographic consequence. Ecological memory may therefore stabilize, destabilize or leave population trajectories unchanged depending on information reliability, environmental change and how memory-shaped movement affects survival, reproduction, recruitment or coexistence.
