CHOOSING a mate explains a puzzling rule of nature, which says the difference in size between males and females increases the larger the animal.
A study of 102 shorebird species by Tamás Székely of the University of Bath, UK, suggests mate selection drives the disparity in size rather sparse resources, as some biologists believe.
In large shorebirds such as gulls males are larger and compete for mates on the shore, where their size is an advantage (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0404503101). But in smaller species, such as dunlin, the females are larger and select…
