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Animals that rely on electrolocation and echolocation for navigation and prey detection benefit from sensory systems that operate in the dark, exploiting a sensory niche with few competitors. Active sensing can be described as a highly specialized form of communication, with the self as both sender and receiver of sensory information. However, the overlapping functions of active sensing as communication with the self and active sensing as communication with others creates challenges for signal privacy and fidelity by leaving active sensing animals vulnerable to eavesdropping, jamming, and noise. Here we present an overview of active sensing systems used by weakly electric fish, bats and odontocetes and consider their susceptibility to heterospecific and conspecific jamming signals and eavesdropping. Susceptibility to jamming signals by both conspecifics and prey animals reduces the efficacy of electrolocation and echolocation for prey capture and foraging. Likewise, active sensing signals may be eavesdropped, opening risk of predation or competition at productive foraging sites. The evolutionary success of these animals suggests that they effectively counter the costs of active sensing through rich and diverse adaptive behaviors that allow them to mitigate the effects of competition for signal space and the exploitation of their signals for social communication.
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Tactics of evasion: strategies used by signallers to deter eavesdropping enemies from exploiting communication systems
ABSTRACT Eavesdropping predators, parasites and parasitoids exploit signals emitted by their prey and hosts for detection, assessment, localization and attack, and in the process impose strong selective pressures on the communication systems of the organisms they exploit. Signallers have evolved numerous anti‐eavesdropper strategies to mitigate the trade‐off between the costs imposed from signal exploitation and the need for conspecific communication. Eavesdropper strategies fall along a continuum from opportunistic to highly specialized, and the tightness of the eavesdropper–signaller relationship results in differential pressures on communication systems. A wide variety of anti‐eavesdropper strategies mitigate the trade‐off between eavesdropper exploitation and conspecific communication. Antagonistic selection from eavesdroppers can result in diverse outcomes including modulation of signalling displays, signal structure, and evolutionary loss or gain of a signal from a population. These strategies often result in reduced signal conspicuousness and in decreased signal ornamentation. Eavesdropping enemies, however, can also promote signal ornamentation. While less common, this alternative outcome offers a unique opportunity to dissect the factors that may lead to different evolutionary pathways. In addition, contrary to traditional assumptions, no sensory modality is completely ‘safe’ as eavesdroppers are ubiquitous and have a broad array of sensory filters that allow opportunity for signal exploitation. We discuss how anthropogenic change affects interactions between eavesdropping enemies and their victims as it rapidly modifies signalling environments and community composition. Drawing on diverse research from a range of taxa and sensory modalities, we synthesize current knowledge on anti‐eavesdropper strategies, discuss challenges in this field and highlight fruitful new directions for future research. Ultimately, this review offers a conceptual framework to understand the diverse strategies used by signallers to communicate under the pressure imposed by their eavesdropping enemies.
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- Award ID(s):
- 2054636
- PAR ID:
- 10390524
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Biological Reviews
- Volume:
- 98
- Issue:
- 1
- ISSN:
- 1464-7931
- Page Range / eLocation ID:
- p. 222-242
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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