RT Journal Article
SR Electronic
T1 Meta-analysis challenges a textbook example of status signalling: evidence for publication bias
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 283150
DO 10.1101/283150
A1 Alfredo Sánchez-Tójar
A1 Shinichi Nakagawa
A1 Moisès Sánchez-Fortún
A1 Dominic A. Martin
A1 Sukanya Ramani
A1 Antje Girndt
A1 Veronika Bókony
A1 Bart Kempenaers
A1 András Liker
A1 David F. Westneat
A1 Terry Burke
A1 Julia Schroeder
YR 2018
UL http://biorxiv.org/content/early/2018/03/16/283150.abstract
AB The status signalling hypothesis aims to explain conspecific variation in ornamentation by suggesting that some ornaments signal dominance status. Here, we use multilevel meta-analytic models to challenge the textbook example of this hypothesis, the black bib of house sparrows (Passer domesticus). We conducted a systematic review, and obtained raw data from published and unpublished studies to test whether dominance rank is positively associated with bib size across studies. Contrary to previous studies, our meta-analysis did not support this prediction. Furthermore, we found several biases in the literature that further question the support available for the status signalling hypothesis. First, the overall effect size of unpublished studies was zero, compared to the medium effect size detected in published studies. Second, the effect sizes of published studies decreased over time, and recently published effects were, on average, no longer distinguishable from zero. We discuss several explanations including pleiotropic, population- and context-dependent effects. Our findings call for reconsidering this established textbook example in evolutionary and behavioural ecology, raise important concerns about the validity of the current scientific publishing culture, and should stimulate renewed interest in understanding within-species variation in ornamental traits.