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Animal choruses emerge from receiver psychology

View Article: PubMed Central - PubMed

ABSTRACT

Synchrony and alternation in large animal choruses are often viewed as adaptations by which cooperating males increase their attractiveness to females or evade predators. Alternatively, these seemingly composed productions may simply emerge by default from the receiver psychology of mate choice. This second, emergent property hypothesis has been inferred from findings that females in various acoustic species ignore male calls that follow a neighbor’s by a brief interval, that males often adjust the timing of their call rhythm and reduce the incidence of ineffective, following calls, and from simulations modeling the collective outcome of male adjustments. However, the purported connection between male song timing and female preference has never been tested experimentally, and the emergent property hypothesis has remained speculative. Studying a distinctive katydid species genetically structured as isolated populations, we conducted a comparative phylogenetic analysis of the correlation between male call timing and female preference. We report that across 17 sampled populations male adjustments match the interval over which females prefer leading calls; moreover, this correlation holds after correction for phylogenetic signal. Our study is the first demonstration that male adjustments coevolved with female preferences and thereby confirms the critical link in the emergent property model of chorus evolution.

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Elaborate chorusing in E. diurnus.Multi-channel oscillogram of a representative 15-s sample of calling recorded from a 4-male chorus in the Peyriac de Mer population (Fig. 4A). See Supplementary note S1 on the occurrence of both synchrony and alternation.
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f2: Elaborate chorusing in E. diurnus.Multi-channel oscillogram of a representative 15-s sample of calling recorded from a 4-male chorus in the Peyriac de Mer population (Fig. 4A). See Supplementary note S1 on the occurrence of both synchrony and alternation.

Mentions: An alternative to the adaptationist paradigm above, and a key to its thorough examination, is the hypothesis that the collective singing patterns in choruses, so conspicuous to human observers, simply emerge from the ‘receiver psychology’16 of female perception and preference101517. For want of explicit experiments conducted on appropriate chorusing species, the hypothesis has been especially conjectural. But recent neuroethological studies of female preference point toward a specific 3-step pathway along which basic perception and sexual selection could ultimately lead to chorusing: In various acoustic species females prefer male calls that precede a neighbor’s call by a brief interval18, a variant of the precedence effects known from psychoacoustic research19. The next step in the pathway is the finding in many species which sing rhythmically that when a male hears a song stimulus, he delays his subsequent call via a mechanism involving momentary inhibition of his central rhythm generator and resetting of his phase relative to that stimulus910 (Fig. 1). Finally, when multiple males use equivalent mechanisms an expansive chorus comprised of synchrony and/or alternation may arise20 (Supplementary note S1). These collective outcomes are predicted by Monte Carlo simulation, and they are consistent with observations of synchrony and alternation in various acoustic insects and anurans21 (Fig. 2). Importantly, the display can be generated in the absence of any selection expressly favoring synchrony or alternation.


Animal choruses emerge from receiver psychology
Elaborate chorusing in E. diurnus.Multi-channel oscillogram of a representative 15-s sample of calling recorded from a 4-male chorus in the Peyriac de Mer population (Fig. 4A). See Supplementary note S1 on the occurrence of both synchrony and alternation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037466&req=5

f2: Elaborate chorusing in E. diurnus.Multi-channel oscillogram of a representative 15-s sample of calling recorded from a 4-male chorus in the Peyriac de Mer population (Fig. 4A). See Supplementary note S1 on the occurrence of both synchrony and alternation.
Mentions: An alternative to the adaptationist paradigm above, and a key to its thorough examination, is the hypothesis that the collective singing patterns in choruses, so conspicuous to human observers, simply emerge from the ‘receiver psychology’16 of female perception and preference101517. For want of explicit experiments conducted on appropriate chorusing species, the hypothesis has been especially conjectural. But recent neuroethological studies of female preference point toward a specific 3-step pathway along which basic perception and sexual selection could ultimately lead to chorusing: In various acoustic species females prefer male calls that precede a neighbor’s call by a brief interval18, a variant of the precedence effects known from psychoacoustic research19. The next step in the pathway is the finding in many species which sing rhythmically that when a male hears a song stimulus, he delays his subsequent call via a mechanism involving momentary inhibition of his central rhythm generator and resetting of his phase relative to that stimulus910 (Fig. 1). Finally, when multiple males use equivalent mechanisms an expansive chorus comprised of synchrony and/or alternation may arise20 (Supplementary note S1). These collective outcomes are predicted by Monte Carlo simulation, and they are consistent with observations of synchrony and alternation in various acoustic insects and anurans21 (Fig. 2). Importantly, the display can be generated in the absence of any selection expressly favoring synchrony or alternation.

View Article: PubMed Central - PubMed

ABSTRACT

Synchrony and alternation in large animal choruses are often viewed as adaptations by which cooperating males increase their attractiveness to females or evade predators. Alternatively, these seemingly composed productions may simply emerge by default from the receiver psychology of mate choice. This second, emergent property hypothesis has been inferred from findings that females in various acoustic species ignore male calls that follow a neighbor’s by a brief interval, that males often adjust the timing of their call rhythm and reduce the incidence of ineffective, following calls, and from simulations modeling the collective outcome of male adjustments. However, the purported connection between male song timing and female preference has never been tested experimentally, and the emergent property hypothesis has remained speculative. Studying a distinctive katydid species genetically structured as isolated populations, we conducted a comparative phylogenetic analysis of the correlation between male call timing and female preference. We report that across 17 sampled populations male adjustments match the interval over which females prefer leading calls; moreover, this correlation holds after correction for phylogenetic signal. Our study is the first demonstration that male adjustments coevolved with female preferences and thereby confirms the critical link in the emergent property model of chorus evolution.

No MeSH data available.


Related in: MedlinePlus