Complex choice environments shelter unattractive signallers from sexual selection
Data files
Jul 03, 2025 version files 157.10 KB
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NSF-BSF_Aim1_Data_Dryad.csv
152.13 KB
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README.md
4.97 KB
Abstract
For many animals, options abound when choosing a mate in socially complex environments like a breeding chorus or lek. In such environments, receivers often choose their mate based on individual differences in signal repetition rate. However, signallers also differ in the regularity with which they produce repeated signals. Irregularity in signalling introduces uncertainty in decision-making by masking the among-individual variation in signalling rate that is a target of mate choice. At present, we know little about how the complexity of the choice environment impacts selection on rate and regularity, two signalling behaviours that receivers can only compare after sampling series of signals produced by multiple signallers. In this study of female grey treefrogs (Hyla chrysoscelis), we measured multivariate sexual selection on the rate and regularity of male calling behaviour using two-, four-, and eight-choice tests. Receivers overwhelmingly chose faster, more regular calling rates in two-choice tests, but did so markedly less often when they chose among four or eight stimuli. Signalling behaviour became much less predictive of signallers’ relative fitness as choice complexity increased, suggesting noise and choice overload effects may shelter male phenotypes from sexual selection imposed by female choice in complex social environments.
https://doi.org/10.5061/dryad.gb5mkkx1v
Description of the data and file structure
We measured sexual selection on call rate and call regularity (the coefficient of variation within males in call rate; standard deviation scaled by the mean) in Cope’s gray treefrog* Hyla chrysoscelis*. We used phonotaxis tests of gravid gray treefrog females to infer how the selection was acting on male phenotypes in choice set sizes of 2, 4, or 8 competing males. We generated ‘stimulus sets’ of 8 hypothetical male phenotypes by drawing their mean values from normal distributions to make a distribution representing their unique combination of call rate and regularity. Then we drew each instantaneous call rate in a sequence of calls from that distribution to generate an audio track that had some given level of rate and regularity. Complete details are given in the paper.
Files and variables
File: NSF-BSF_Aim1_Data_Dryad.csv
Description:
These are data from phonotaxis tests of gravid gray treefrog females. Data are organized around the hypothetical male phenotypes females chose among: there is one row for each hypothetical male (identified by SpeakerNumer) per choice set size (2, 4, or 8) per female (identified by FemaleID), such that females have 24 rows of data (8 rows from eight-choice tests; 8 rows from four-choice tests; 8 rows from two-choice tests).
Variables
- FemaleID: This is an alphanumeric code given to identify each female in the dataset. The codes all begin with the species code “Hch” for “Hyla chrysoscelis” and end with the year code “-23” for 2023. The three digit code between “Hch” and “-23” uniquely identify each female.
- StimulusSet: This numeric code identifies which of the ‘stimulus sets’ of 8 hypothetical males a female was tested with. No more than two females were assigned to any one stimulus set.
- SpeakerNumber: This numeric code identifies the spatial location of a speaker in the testing arena. Speakers were arrayed around the edge of a 2 m diameter circle in order 1-8. Adjacent speakers were separated by 45 degrees.
- NumStimuli: This numeric code identifies the number of stimuli in the choice set for a given trial. Possible values are 2, 4, or 8.
- CR_Nominal: This value is the calling rate of the hypothetical male measured in calls per minute (cpm).
- CVw_Nominal: This value is the coefficient of variation in calling rate of the hypothetical male. This value is calculated by scaling the standard deviation in calling rate by the mean calling rate.
- Responses: A count of how many phonotaxis trials in which the hypothetical male was chosen. The maximum value in 8-choice tests is 4; the maximum value in 4-choice tests is 2; the maximum value in 2-choice tests is 1.
- Latency_1: The latency (seconds) measures the time elapsed between when the frog was released from the center of the arena and when she passed into a choice bin near a speaker. There are up to four latencies for a given hypothetical male phenotype (each row of the dataset), if that hypothetical male phenotype were chosen in all four eight-choice tests in which it appeared. There are up to two latencies for a given hypothetical male phenotype (each row of the dataset), if that hypothetical male phenotype was chosen in both four-choice tests in which it appeared. There is up to one latency value for a given hypothetical male phenotype (each row of the dataset) in a two-choice test, if that male phenotype was chosen in the two-choice test in which it appeared. Cells marked “NA” reflect that that male phenotype was not chosen in a particular trial. For four- and eight- choice tests in which it is possible to have more than one latency value because of repeated testing with those stimuli within female subjects, the order (Latency1-4) reflects testing order such that Latency1 is the first time that stimulus was chosen, Latency_2 the second time, and so on.
- Latency_2: See detailed explanation under Latency_1.
- Latency_3: See detailed explanation under Latency_1.
- Latency_4: See detailed explanation under Latency_1.
- Rel_Fitness: The relative fitness of a hypothetical male phenotype calculated by dividing the number of responses by the choice set size. This value was always bounded by 0 and 0.5 such that if a male was chosen in the single two-choice test in which he appeared, he would score a relative fitness of 1/2 or 0.5. If a male was chosen in both of the four-choice tests in which he appeared, he would score a relative fitness of 2/4 or 0.5. If a male was chosen in all four of the eight-choice tests in which he appeared, he would score a relative fitness of 4/8 or 0.5. A male that was never chosen in a choice test in which he appeared would score a 0.
Code/software
NA
Access information
These are original data archived nowhere else.
These are data generated from phonotaxis (movement toward sound) of female gray treefrogs Hyla chrysoscelis. We calculated the Relative Fitness score for each hypothetical male phenotype in the dataset by dividing the number of times he