Traffic noise exposure impacts song production in wild male field crickets (Gryllus bimaculatus) under predator and intrasexual competition contexts
Data files
Apr 23, 2025 version files 277.52 KB
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Antipredator_response.csv
122.86 KB
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Datasets.xlsx
103.24 KB
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GallegoAbenza_Wheatcroft_Statistical_analyses.R
37.63 KB
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Latency_to_resume_chirping.csv
9.78 KB
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README.md
4 KB
Abstract
Animals are known to adjust their acoustic signals in the presence of anthropogenic noise. These changes may affect fitness by altering susceptibility to predators or changing signal efficiency in intra and intersexual interactions. Male field crickets, Gryllus bimaculatus, chirp to attract females, with chirp rate being an important success factor. Males reduce chirp rate when exposed to predators or traffic noise and increase it in response to male competitors. However, the combined effects of these pressures on signalling are unknown. This study examined whether antipredator responses are influenced by male-male competition and variation in traffic noise exposure. We used substrate-borne vibrations to simulate a predator approaching calling males and varied perceived male-male competition using playbacks. We found that responses to increased competition were affected by variation in traffic noise exposure, with males chirping faster as noise levels increased. Additionally, antipredator responses depended on an interaction between traffic noise and competition. Under high competition, males reduced chirp rate as traffic noise increased. Our results demonstrate that adjustments in signal production in response to noise pollution may negatively impact communication in both antipredator and competitive contexts, indicating more pervasive effects of anthropogenic noise than previously recognized.
https://doi.org/10.5061/dryad.sn02v6xd3
Dataset structure
Two sheets can be found in the Excel file, named "Antipredator_responses" and "Latency_resume_calling". Both sheets are needed to examine the effect of environmental traffic noise, the presence of a neighbor calling within five meters, and whether the simulated predator was accompanied by a playedback competitor on the calling song of field cricket males. Two .csv files (one for each Excel file tab) are also available under the respective names.
In "Antipredator responses", both pre- and post-threat song features can be found, i.e., ICI_baseline and Number_pulses_baseline, and ICI_response and Number_pulses_response, respectively.
Analyses on the latency to resume calling after threatening crickets are found in the Excel tab "Latency_resume_calling", where only two observations per tested male are found.
ICI_baseline: 10 inter-chirp intervals taken prior to experimentally interrupted song by simulating an approaching predator.
Number_pulses_baseline: Number of pulses of the 10 first chirps before threatening.
ICI_response: 10 inter-chirp intervals taken prior to experimentally interrupted song by simulating an approaching predator.
Number_pulses_response: Number of pulses of the 10 chirps after threatening.
Latency_resume_sec: Latency to resume chirping of threatened crickets.
Environmental_traffic_noise_exposure: Measured in dBs, represents the chronic exposure to traffic noise of each tested male at the location where it was located. This is calculated from the Distance_to_the_road in meters. Calculation is explained in Methods section.
Neighbor_presence5m: (Yes / No), indicates whether the tested male has a calling neighbor within a distance of five meters.
Treatment: (Threat / Threat_plus_played-back_male). It refers to the two simulated predator approaching that each tested cricket male was exposed during the study. In the "Threat_plus_played-back_male", a conspecific calling song was played back 30 seconds before the threat (see Experimental protocol section for more details).
Order_Treatment: (first / second), refers to the order in which the two treatments were presented. We randomized it across tested males.
Tested_male: Tested male found calling at a certain distance from a highway.
Date: format Day/Month/Year - 00/00/0000
Time: format Minute:Hour - 00:00
Highway: Name of the three highways in which the experiments were conducted.
Broadcasting_male: Identity of the three males used for artificially increasing male-male competition during threating (Treatment: Threat_plus_played-back_male).
Measure_allocation: It goes from 1 to 10 and represents the order of measurement taken in Raven Pro.
ICI_baseline_mean: Calculated mean of the 10 ICI (Inter-chirp interval) measured before threatening
Number_pulses_baseline_mean: Calculated mean of the pulses per chirp before threatening
ICI_baseline_mean_without_pback_male: Calculated mean of the ICI during baseline and in the treatment Threat
Code/Software
The R script allows
1) analyse the effect of the explanatory variables on "Latency_resumesec"
2) examine the effect of male-male competition on chirp rate adjustments (ICI_baseline)
3) calculate "Delta_ICI" = ICI_response - ICI_baseline, and examine the effect of the three-way interaction term composed by Environmental_traffic_noise_exposure, Neighbor_presence5m and Treatment on it.
Codes for variables transformation, predicted & raw data plotting as well as model comparison using likelihood ratio tests, are included in the R script.