Experimental evidence that chronic outgroup conflict reduces reproductive success in a cooperatively breeding fish
- School of Biological Sciences/Life Sciences, University of Bristol, United Kingdom
Figures
Figure 1
Experimental setup and timelines.
(A) Experimental setup showing a linearly arranged tank triplet, with size-matched experimental groups (Intruded and Control) at the ends and the tank with the neighbour pair at the centre. The female neighbour is presented in the Intruded group tank to illustrate an intrusion along the border of the resident group’s territory. (B) Timelines show measures of general reproductive behaviour (orange), egg and parental-care investment (green), and reproductive output (purple).
Figure 2
Defensive actions.
(A) Group defensive actions displayed per 10-min trial, towards a transparent partition (blue) or the intruding female neighbour (red) in weeks 1 and 11 of Experiment I (N = 20 groups). (B) The number of defensive actions displayed by the dominant female (DF, N = 10), dominant male (DM, N = 10), and subordinate (S, N = 6) towards the intruding female neighbour during weeks 1 (green) and 11 (yellow) of Experiment I. Boxplots show medians, 25% and 75% quartiles, and whiskers representing 95% confidence intervals; dots are raw data, with lines connecting matched groups (A) or repeated measures on individuals (B).
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Figure 2—source data 1
Number of group defensive actions displayed per 10-minute trial, towards a transparent partition (Control treatment) or the intruded female (Intruded treatment) in weeks 1 and 11 of Experiment I (n = 20 groups); and number of defensive actions displayed by the dominant females (DF, n = 10), dominant male (DM, n = 10), and subordinate (S, n = 6) per 10-minute trial, towards the intruding female neighbour during weeks 1 and 11 of Experiment I.
- https://cdn.elifesciences.org/articles/72567/elife-72567-fig2-data1-v1.xlsx
Figure 3
Effects of chronically elevated outgroup conflict on reproductive rate and egg investment.
Effects of chronically elevated outgroup conflict (red) relative to control conditions (blue) on: (A) inter-clutch interval (N = 21 intervals); (B) clutch size (N = 34 clutches); (C) egg volume (N = 15 clutches); and (D) egg protein content (N = 15 clutches). All panels depict predicted means and associated 95% confidence intervals; dots are raw data.
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Figure 3—source data 1
Inter-clutch intervals (days, n = 21 intervals); clutch size (number of eggs, n = 34 clutches); volume of eggs (mm^3, n = 15 clutches); and egg protein content (micrograms, n = 15 clutches), of clutches produced by Control and Intruded groups.
- https://cdn.elifesciences.org/articles/72567/elife-72567-fig3-data1-v1.xlsx
Figure 4
Effect of chronically elevated outgroup conflict on parental-care investment and hatching success.
Effects of chronically elevated outgroup conflict (red) relative to control conditions (blue) on: (A) number of clutch visits (N = 33 clutches); (B) number of clutch caring (cleaning and fanning) events per 10 min observation (N = 33 clutches); and (C) offspring hatching success (N = 21 clutches). All panels depict predicted means and associated 95% confidence intervals; dots are raw data.
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Figure 4—source data 1
Number of clutch visits (n = 33 clutches) and number of clutch caring evens (n = 33 cutches) provided to; and offspring hatching success (n = 21 clutches) of, clutches produced by Control and Intruded groups.
- https://cdn.elifesciences.org/articles/72567/elife-72567-fig4-data1-v1.xlsx
Figure 5
Effect of chronically elevated outgroup conflict on reproductive output.
Effect of chronically elevated outgroup conflict (red) compared to control conditions (blue) on: (A) number of offspring surviving to 1 month (N = 32 clutches); (B) latency to first movement of offspring post-stimulus (N = 21 clutches); (C) mean offspring standard length (N = 24 clutches); and (D) mean offspring dry weight (N = 24 clutches). All panels depict predicted means and associated 95% confidence intervals; dots are partial residuals (A) or raw data (B–D).
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Figure 5—source data 1
Number of offspring surviving to 1-month post hatching (n = 32 clutches); latency for first movement of offspring post-stimulus (n = 21 clutches) in a startling stimulus test; mean offspring standard length (n = 24 clutches); and mean offspring dry weight (n = 24 clutches), from clutches produced by Control and Intruded groups.
- https://cdn.elifesciences.org/articles/72567/elife-72567-fig5-data1-v1.xlsx
Additional files
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Supplementary file 1
Statistical summary of linear mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on breeding timings.
Effect of outgroup conflict on (a) latency to spawn (days) and (b) inter-clutch interval (days); latency to spawn was log10-transformed. Female size relates to dominant female standard length at the start of the study. Tank-triplet and/or group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp1-v1.docx
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Supplementary file 2
Statistical summary of linear mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control) on clutch size.
Effect of outgroup conflict on clutch when females could spawn repeatedly throughout the study (Experiment I). Female size relates to dominant female standard length measurement made closest in time to the production of each clutch (start or end of study). Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Table displays the final model, with removed non-significant interactions below.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp2-v1.docx
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Supplementary file 3
Statistical summary of linear mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment II) on mean morphological and physiological egg characters.
Effect of outgroup conflict on egg (a) volume (mm3), (b) dry weight (mg), (c) lipid content (µg), and (d) protein content (µg). Female size relates to dominant female standard length at the start of the study. Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below. For fixed effects included in significant interactions, only parameter estimates are shown.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp3-v1.docx
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Supplementary file 4
Statistical summary of generalised linear mixed models (GLMMs) testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on the number of parental-care behaviours performed during a 10-min period.
Effect of outgroup conflict on (a) clutch visits and (b) caring (egg-cleaning and fanning) events; both analysed using negative binomial GLMMs with a ‘log’ link function. Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below. For fixed effects included in significant interactions, only parameter estimates are shown.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp4-v1.docx
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Supplementary file 5
Statistical summary of mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on time spent on parental-care behaviour during a 10-min period.
Effect of outgroup conflict on time spent on (a) clutch visits (linear mixed model, LMM) and (b) caring (egg-cleaning and fanning) events (generalised linear mixed model [GLMM] with ‘gaussian’ family and ‘log’ link function). Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below. For fixed effects included in significant interactions, only parameter estimates are shown.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp5-v1.docx
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Supplementary file 6
Statistical summary of a linear mixed model testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on hatching success (%).
Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Table shows the final model with removed non-significant interactions below.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp6-v1.docx
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Supplementary file 7
Statistical summary of a linear mixed model testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on offspring survival to 1-month post-hatching.
Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown); clutch size at laying was included as an offset. The reference level for Treatment was Control. Table displays the final model. For fixed effects included in the significant interaction, only parameter estimates are shown.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp7-v1.docx
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Supplementary file 8
Statistical summary of linear mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on offspring behaviour.
Effect of outgroup conflict on (a) mean pre-stimulus activity (%), (b) mean pre-stimulus nearest-neighbour distance (cm), (c) mean latency to freeze (s) post-stimulus, and (d) latency (s) to become active post-stimulus. Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below. For fixed effects included in significant interactions, only parameter estimates are shown.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp8-v1.docx
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Supplementary file 9
Statistical summary of linear mixed models testing the effect of chronic outgroup conflict (Intruded vs. Control, Experiment I) on offspring size.
Effect of outgroup size on (a) mean standard length (mm) and (b) mean dry weight (mg). Tank-triplet and group identity nested within tank-triplet were fitted as random intercepts (with variances shown). The reference level for Treatment was Control. Each table section displays the final model, with removed non-significant interactions below.
- https://cdn.elifesciences.org/articles/72567/elife-72567-supp9-v1.docx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/72567/elife-72567-transrepform1-v1.pdf
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Source data 1
Source data for all statistical analyses (data for each separate analysis are provided in separate labelled worksheets).
- https://cdn.elifesciences.org/articles/72567/elife-72567-data1-v1.xlsx
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Experimental evidence that chronic outgroup conflict reduces reproductive success in a cooperatively breeding fish
eLife 11:e72567.
https://doi.org/10.7554/eLife.72567
