Animal signal

A feature or action shaped by selection for its effects on a receiver, with receiver responses also subject to selection. A merely informative incidental feature can instead be a biological cue.

A relation between a signal and a property relevant to its receiver. Honesty can follow aligned interests, physical constraints or differential costs and benefits; high production cost alone does not establish it.

Signalling in which costs contribute to the evolutionary incentives governing expression. Reliability depends on differences in net payoffs among signaller types, not merely on a signal being expensive.

A signal whose relation to the advertised property is constrained by its production mechanism. The receiver’s use and the relevant physical constraint should both be tested.

Communication using more than one sensory modality. Components can supply redundant information, different information or context-dependent detection benefits.

The sensory channel through which a signal acts, such as acoustic, visual, chemical, mechanical or electrical stimulation.