title: Ontogenic differences in sexual size dimorphism across four plover populations.
abstract: Sexual size dimorphism (SSD) among adults is commonly observed in animals and is considered to be adaptive. However, the ontogenic emergence of SSD, i.e. the timing of divergence in body size between males and females, has only recently received attention. It is widely acknowledged that the ontogeny of SSD may differ between species, but it remains unclear how variable the ontogeny of SSD is within species. Kentish PloversCharadrius alexandrinusand Snowy PloversC. nivosusare closely related wader species that exhibit similar, moderate (c. 4%), male-biased adult SSD. To assess when SSD emerges we recorded tarsus length variation among 759 offspring in four populations of these species. Tarsus length of chicks was measured on the day of hatching and up to three times on recapture before fledging. In one population (Mexico, Snowy Plovers), males and females differed in size from the day of hatching, whereas growth rates differed between the sexes in two populations (Turkey and United Arab Emirates, both Kentish Plovers). In contrast, a fourth population (Cape Verde, Kentish Plovers) showed no significant SSD in juveniles. Our results suggest that adult SSD can emerge at different stages of development (prenatal, postnatal and post-juvenile) in different populations of the same species. We discuss the proximate mechanisms that may underlie these developmental differences.
authors: Department of Biology and Biochemistry University of Bath Claverton Down Bath BA2 7AY UK; NERC-Biomolecular Analysis Facility Department of Animal and Plant Sciences University of Sheffield Western Bank Sheffield S10 2TN UK.
authors: Natalie
authors: N
authors: Dos Remedios
authors: Department of Biology and Biochemistry University of Bath Claverton Down Bath BA2 7AY UK.
authors: Tamás
authors: T
authors: Székely
authors: NERC-Biomolecular Analysis Facility Department of Animal and Plant Sciences University of Sheffield Western Bank Sheffield S10 2TN UK.
authors: Clemens
authors: C
authors: Küpper
authors: Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Warrnambool Victoria 3280 Australia; Department of Biosciences College of Science Swansea University Singleton Park Swansea SA2 8PP UK.
authors: Patricia L M
authors: PL
authors: Lee
authors: MTA-DE 'Lendület' Behavioural Ecology Research Group Department of Evolutionary Zoology University of Debrecen Egyetem tér 1. H-4032 Debrecen Hungary.
authors: András
authors: A
authors: Kosztolányi
keywords: Charadriiformes; development; growth; ontogeny; sexual size dimorphism; tarsus; waders