Allometry, sexual dimorphism, and sexual trait elaboration in the birds-of-paradise

Title (eng)
Allometry, sexual dimorphism, and sexual trait elaboration in the birds-of-paradise
Author
Thomas MacGillavry
Author
Leonida Fusani
Author
Ken S. Toyama
Abstract (eng)
Rensch's rule (RR) is a widespread macroevolutionary pattern describing a positive association between male-biased dimorphism and species size. Applied to sexual size dimorphism, RR is often associated with sexual selection, as larger body sizes may benefit males in competition and courtship. Moreover, the presence of RR in sexual traits further indicates that males reap relative performance benefits beyond large body size alone. Here we describe patterns of elaboration, variation, and sexual dimorphism in tail length in the birds-of-paradise (Aves: Paradisaeidae), which exhibit an extreme diversity in tail lengths, ranging from short-tailed species to the longest-tailed passeriform birds. We found that body size followed RR in polygynous, but not monogamous species, in accordance with the sexual selection hypothesis. However, we found no evidence of RR in tail length, indicating similar evolutionary allometries between males and females. Evolutionary allometries of male and female traits were both strongly positive among long-tailed species, suggesting that the lack of RR results from phenotypic correlations between the sexes, rather than constraints on ornament exaggeration. Our study represents the first integrative test of RR in an ornamental morphological trait and evidences how different aspects of dimorphism interact in a group with a hyperdiverse courtship trait.
Remark (eng)
Online Version of Record before inclusion in an issue
Type (eng)
journal article
Language
[eng]
Persistent identifier
https://phaidra.vetmeduni.ac.at/o:4781
DOI
10.1093/evolut/qpaf263
Is in series
Title (deu)
Evolution
ISSN
0014-3820
Issued
2025
Number of pages
13
Publication
Oxford University Press
Version type (eng)
version of record (published version)
Date issued
2025
Access rights (eng)
open access
License
CC BY 4.0 International
Rights statement (eng)
© The Author(s) 2025