Evolutionary Biology

A systematic review and meta-analysis of anti-predator mechanisms of eyespots: conspicuous pattern vs eye mimicry

Ayumi Mizuno author has email address
Malgorzata Lagisz
Pietro Pollo
Yefeng Yang
Masayo Soma
Shinichi Nakagawa

Department of Biology, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan
Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
Theoretical Sciences Visiting Program, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan

https://doi.org/10.7554/eLife.96338.2

Open access
Copyright information

Figures and data

A visual summary of three hypotheses that explain the predation avoidance function of eyespot patterns and the predictions that can be derived from these two hypotheses. The resemblance of eye spots to actual eyes is discussed through the predator mimicry hypothesis and the conspicuous signal hypothesis. The table shows the predictions derived from these two hypotheses.

Descriptions of the population, Intervention, comparator, and outcome (PICO) used to define the scope of this study.

Overview of the dataset. (a) shows a PRISMA-like flowchart of the systematic literature search for the meta-analysis. (b) and (c) give details of the main moderators examined in the meta-analysis. (d) provides the phylogenetic tree of bird species included in the meta-analysis, together with the sample sizes and number of effect sizes per species.

Mean effect sizes of (a) overall for all highly salient patterns, (b) effects split by experiments with eyespots versus conspicuous patterns, and (c) two prey types used in the experiments. Thick horizontal lines represent 95% confidence intervals, and thin horizontal lines represent 95% prediction intervals. The points in the centre of each thick line indicate the average effect size. k is the number of effect sizes used to estimate the statistics, followed by the number of studies in the brackets.

The relationships between (a) prey salient pattern area (log-transformed) and effect sizes and (b) number of prey salient patterns and effect sizes. Circle sizes are scaled according to precision, k represents the number of effect sizes. Each fitted regression line is shown as a coloured straight line, and 95% confidence and prediction intervals are shown as dashed and dotted coloured lines, respectively.

(a) Funnel plot using effect size and its inverse standard error. The relationship between effect sizes and (b) the square root of the inverse of effective sample size and (c) publication year. In (b) and (c), circle sizes are scaled accordingly to precision, and k represents the number of effect sizes. Each fitted regression line is shown as a straight line, and 95% confidence and prediction intervals are shown as dashed and dotted lines, respectively.

The relationships between (a) total pattern area, (b) pattern maximum diameter/length, and (c) total prey surface area and effect sizes. k shows the number of effect sizes. Each fitted regression line is shown as a solid straight line, and 95%confidence and prediction intervals are shown as dashed and dotted lines, respectively.

Mean effect sizes of total prey shape types. Thick horizontal lines represent 95% confidence intervals, and thin horizontal lines represent prediction intervals. The points in the centre of each thick line indicate the average effect size. k shows the number of effect sizes.

(a) relationship between effect size and the square root of the inverse of effective sample size, and (b) relationship between effect size and publication year. Both plots were based on the multi-moderator model. k shows the number of effect sizes. Each fitted regression line is shown as a solid straight line, and 95% confidence intervals and prediction intervals are shown as dashed and dotted lines, respectively.

PRISMA-EcoEvo Checklist.

PRISMA-EcoEvo Checklist.

Search strings used for each database. We accessed Scopus, ISI Web of Science core collection, Google Scholar (Japanese, Polish, Portuguese, Russian, Spanish, Simplified Chinese, and Traditional Chinese) on 08/06/2023, and Bielefeld Academic Search Engine (BASE) on 26/06/2023. BASE was used as a source of grey literature. We conducted backward and forward reference searches for key review articles using Scopus on 19/06/2023. We modified search strings to collect studies to capture studies examining the effects of eyespot patterns on birds using experimental methods. Search strings were adapted to the structure of each database.

Search strings used for each database. We accessed Scopus, ISI Web of Science core collection, Google Scholar (Japanese, Polish, Portuguese, Russian, Spanish, Simplified Chinese, and Traditional Chinese) on 08/06/2023, and Bielefeld Academic Search Engine (BASE) on 26/06/2023. BASE was used as a source of grey literature. We conducted backward and forward reference searches for key review articles using Scopus on 19/06/2023. We modified search strings to collect studies to capture studies examining the effects of eyespot patterns on birds using experimental methods. Search strings were adapted to the structure of each database.

List of (a)included and (b) excluded studies at the full-text screening stage with exclusion reasons.

List of (a)included and (b) excluded studies at the full-text screening stage with exclusion reasons.

Summary of a multi-moderator model including all moderators. The bold typeface is used when a 95% confidence interval (CI) does not contain zero; thus, it can be interpreted as an existing significant effect in predator avoidance.

Average maximum diameter of Eyespots on Bicyclus anynana. AM obtained the pictures from lepdata.org/photos/animals/ and https://data.nhm.ac.uk/ and measured the eyespot diameters. Raw data is https://ayumi-495.github.io/eyespot/.

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