Non-Visual Communication in Freshwater Benthos: An Overview

Abstract

This overview of non-visual communication in freshwater benthic animals emphasizes recent studies of the effect of chemical and mechanical signals on predator-prey interactions of benthic macroinvertebrates and amphibians. Prey species use chemical signals to modify their morphological development, life history strategy, feeding, and predator avoidance behavior. The advantages of chemical signals are that they can be used in dark or turbid environments by animals that do not have image-forming eyes. Chemical signals are more persistent than mechanical signals, and they allow species-level identification of predator species. In streams, prey species may use mechanical signals (hydrodynamic pressure waves or sound) to avoid predators approaching from downstream (a situation characteristic of streams and in which chemical signals are unreliable) and to initiate escape responses. Predators often depend on chemical signals to stimulate or inhibit feeding, and they use species-specific mechanical signals to locate or track prey or potential mates. The exact nature of non-visual signals depends on ecological constraints of both the sender and receiver. Responses to non-visual signals may be adapted to local predator conditions. Non-visual signals are effectively used over a wide range of temporal and spatial scales in all aquatic habitats. Organisms often adjust their responses as ontogenic development results in changing size, diet, and habitat.