Data from: Frogs with a southern drawl: Wide recognition space facilitates heterospecific aggression in territorial cricket frogs
Data files
Dec 16, 2025 version files 24.06 KB
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Playback_response_analysis.R
8.71 KB
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Playback_response_data.csv
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README.md
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Abstract
Species recognition enables both females and males to make adaptive behavioral decisions in sympatric zones. Research on species recognition usually concentrates on how female mate choice prevents interspecies matings. Male-male competition also plays an important role in reproduction but is relatively understudied in the context of speciation. The present study investigates the aggressive thresholds for species recognition during male-male competition in northern and southern cricket frogs: two sympatric “sibling” species of frogs that are distinguishable based on advertisement calls. We conducted a field playback experiment that presented synthetic calls to male northern cricket frogs (Acris crepitans) that varied in temporal properties, spanning the range from conspecific to heterospecific call properties. Males responded aggressively to calls ranging from average conspecific calls to average heterospecific calls, notably excluding extreme heterospecific calls. We also modeled how optimal thresholds for species recognition depend on local proportions of conspecific and heterospecific individuals, and predicted as optimal the thresholds we measured under conditions of very few heterospecifics. Overall, our results show that recognition space for territorial aggression in male A. crepitans is larger than signal space, and their thresholds for recognition would enable heterospecific aggression. Such thresholds could be adaptive under social environments dominated by conspecifics, or in noisy choruses in which males compete with both conspecifics and heterospecifics to attract females by minimizing acoustic interference from rivals.
Dataset DOI: 10.5061/dryad.q2bvq83x8
Description of the data and file structure
Files and variables
File: Playback_response_data.csv
Description: This data set includes all behavioral data from 40 paired field playbacks conducted on 20 male northern cricket frogs (Acris crepitans) in the summer of 2023. All field playbacks were conducted in Lake Matoaka in Williamsburg, Virginia. These data represent visual observations from playback trials and acoustic measurements from recordings of calling behavior. Note: Any cells left blank are due to the infeasibility of getting the data (i.e., the focal male escaped before physical measurements could be taken, aquatic vegetation prevented sightlines, etc.), or the male not calling during that trial period.
Variables
- Recording: The unique file number of the recording.
- Treatment: The synthetic call stimulus presented to the male during the stimulus period. "Ac" = conspecific, "H" = hybrid, "Ag" = heterospecific, and "AgX" = extreme heterospecific.
- ID: The individual male tested. Efforts were made to avoid testing the same individuals repeatedly (see manuscript for more details).
- Stim_Period: This reflects either the pre-stimulus, stimulus, or post-stimulus period for each trial. Each of these periods lasted 4 minutes and males were given approximately 10 minutes between paired trials before the next pre-stimulus period.
- Total_Calls: The number of calls made by the male.
- Avg_Click_Rate: The average click rate throughout the period, calculated as the average of the number of clicks per call divided by their duration for all calls in the period (clicks/second).
- Avg_Call_Dur: The average call duration (seconds).
- Avg_Num_Clicks: The average number of clicks per call.
- Avg_Dom_Freq: The average dominant frequency between all calls (Hz).
- Avg_Click_Dur3: The average duration of clicks, calculated from the first, median, and last calls in the period (seconds).
- Avg_Pulses3: The average number of pulses per click, calculated from the first, median, and last calls in the period.
- Avg_Click_Rate3: The average click rate, calculated from the first, median, and last calls in the period (clicks/second).
- Avg_Pulse_Rate3: The average pulse rate, calculated from the first, median, and last calls in the period (pulses/second).
- Date: The date of the start of the trial.
- Temp_C: The temperature of the air close to the surface of the water where the frog was calling, taken with a field thermometer (C).
- AlwaysInflated: A binary variable with "1" indicating that the male remained inflated during the entire trial.
- Orientation: A binary variable with "1" indicating that the male oriented towards the speaker during the stimulus period.
- App_Dist_prop: The proportion of the SPL Distance that the frog covered in approaching the speaker, if applicable.
- FootFlags: An integer variable for the number of foot flags observed.
File: Playback_response_analysis.R
Description: This R code includes all of our analyses of the behavioral response data from playbacks (Playback_response_data.csv) from the paper, as well as the code for generating our figures. We first correct the data for temperature, then continue on to construct a PCA of call and behavioral variables to generate an aggression index, and finally, perform statistical tests on select call variables and our aggression index to determine whether responses differed across treatments.