Sexual selection on brain size in shorebirds (Charadriiformes)

Natural selection is considered a major force shaping brain size evolution in vertebrates, whereas the influence of sexual selection remains controversial. On one hand, sexual selection could promote brain enlargement by enhancing cognitive skills needed to compete for mates. On the other hand, sexu...

Full description

Saved in:
Bibliographic Details
Published in:Journal of evolutionary biology 2013-04, Vol.26 (4), p.878-888
Main Authors: García‐Peña, G. E., Sol, D., Iwaniuk, A. N., Székely, T.
Format: Article
Language:English
Subjects:
Animals
Biological Evolution
Birds
body size evolution
Body Weight
Brain
Brain - anatomy & histology
Charadriidae
Charadriiformes
Charadriiformes - anatomy & histology
Charadriiformes - classification
Charadriiformes - genetics
Evolutionary biology
Female
Genetics
life histories
Male
Models, Biological
Organ Size
parental care
Phenotype
Phylogeny
Selection, Genetic
Sex Factors
Sexual Behavior, Animal
Size
Testis - anatomy & histology
trade‐off
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Natural selection is considered a major force shaping brain size evolution in vertebrates, whereas the influence of sexual selection remains controversial. On one hand, sexual selection could promote brain enlargement by enhancing cognitive skills needed to compete for mates. On the other hand, sexual selection could favour brain size reduction due to trade‐offs between investing in brain tissue and in sexually selected traits. These opposed predictions are mirrored in contradictory relationships between sexual selection proxies and brain size relative to body size. Here, we report a phylogenetic comparative analysis that highlights potential flaws in interpreting relative brain size‐mating system associations as effects of sexual selection on brain size in shorebirds (Charadriiformes), a taxonomic group with an outstanding diversity in breeding systems. Considering many ecological effects, relative brain size was not significantly correlated with testis size. In polyandrous species, however, relative brain sizes of males and females were smaller than in monogamous species, and females had smaller brain size than males. Although these findings are consistent with sexual selection reducing brain size, they could also be due to females deserting parental care, which is a common feature of polyandrous species. Furthermore, our analyses suggested that body size evolved faster than brain size, and thus the evolution of body size may be confounding the effect of the mating system on relative brain size. The brain size‐mating system association in shorebirds is thus not only due to sexual selection on brain size but rather, to body size evolution and other multiple simultaneous effects.
ISSN:1010-061X
1420-9101
DOI:10.1111/jeb.12104