DOI: 10.5061/dryad.ck858
title: Data from: Real-time social selection maintains honesty of a dynamic visual signal in cooperative fish

description: Our understanding of animal communication has been largely driven by
 advances in theory since empirical evidence has been difficult to obtain.
 Costly signaling theory became the dominant paradigm explaining the
 evolution of honest signals, according to which communication reliability
 relies on differential costs imposed on signalers to distinguish animals
 of different quality. On the other hand, mathematical models disagree on
 the source of costs at the communication equilibrium. Here we present an
 empirical framework to study the evolution of honest signals that
 generates predictions on the form, function and sources of reliability of
 visual signals. We test these predictions on the facial color patterns of
 the cooperatively breeding Princess of Burundi cichlid, Neolamprologus
 brichardi. Using theoretical visual models and behavioral experiments we
 show that these patterns possess stable chromatic properties for efficient
 transmission in the aquatic environment, while dynamic changes in signal
 luminance are used by the fish to communicate switches in aggressive
 intent. By manipulating signal into out-of-equilibrium expression and
 simulating a cheater invasion, we demonstrate that social costs (receiver
 retaliation) promote the honesty of this dynamic conventional signal. By
 directly probing the sender of a signal in real time, social selection is
 likely to be the mechanism of choice shaping the evolution of inexpensive,
 yet reliable context-dependent social signals in general.
description: EyelinerReflectance data of black waterproof liquid eyeliner (Collection 2000, USA) used to manipulate the horizontal facial stripe of Neolamprologus brichardi.Lens_TransmittanceNormalized transmittance of Neolamprologus brichardi crystalline lens.Metriaclima_zebra_spectral_sensitivitiesSpectral sensitivities of Metriaclima zebra opsins used to model Neolamprologus brichardi vision.Mirror_Stripe_ManipulationBehavioral data from standard mirror image stimulation testing stripe manipulation.Normalized_Downwelling_IrradianceNormalized downwelling irradiance at Lake Tanganyika, Zambia, Isanga Bay, collected at 7m depth on September 2011 (8:30am).Reflectance_BlueReflectance data of the facial blue patch of Neolamprologus brichardi.Reflectance_Branchiostegal_MembraneReflectance data of the white branchiostegal membrane of Neolamprologus brichardi.Reflectance_HeadReflectance data of the head region of Neolamprologus brichardi.Reflectance_Horizontal_Facial_StripeReflectance data of the horizontal facial stripe of Neolamprologus brichardi.Reflectance_LachrymalReflectance data of the lachrymal region of Neolamprologus brichardi.Reflectance_Vertical_Facial_StripeReflectance data of the vertical facial stripe of Neolamprologus brichardi.Reflectance_YellowReflectance data of the facial yellow patch of Neolamprologus brichardi.Territorial_CombatBehavioral data from dyadic territorial combats of Neolamprologus brichardi.WoundsnowReflectance data of wound snow and wound spray (KOI MED®) used to manipulate the horizontal facial stripe of Neolamprologus brichardi.