Cryptic sexual size dimorphism in Malagasy plovers Charadrius spp.

  • Sama Zefania
  • Razafimahatratra Emilienne
  • Patrícia J Faria
  • Michael W Bruford
  • Peter R Long
  • Tamás Székely

Abstract

Many small plovers Charadrius spp. have sexually monomorphic plumage and cryptic sexual size dimorphism. The objective of our study was to assess the variation in body sizes between male and female plovers breeding in Madagascar. We collected blood samples and data on adult body sizes of four small plovers (Madagascar Plover Charadrius thoracicus, Kittlitz’s Plover C. pecuarius, White-fronted Plover C. marginatus and Three-banded Plover C. tricollaris), and used molecular genetic markers to sex the adults. We found significant differences in body size  among the four species, and between sexes. Furthermore, individuals from the southern ecoregion tended to be larger than in the western ecoregion. The Madagascar Plover’s body size was significantly more  dimorphic than the Kittlitz’s and White-fronted Plovers. Breeding Malagasy plovers’ show significant sexual size dimorphism (SSD): Madagascar Plover females were heavier and had longer wings than  males, whereas the males had longer tarsi; in White-fronted Plover only wing length was different between the sexes. Taken together, our  work reports SSD in small African plovers that exhibit monomorphic plumage, and we propose that SSD may be more common than currently acknowledged; we term this ‘cryptic sexual size dimorphism’. Our results also suggest sexual selection and/or natural selection exert different pressures on body size in different Malagasy plover species.

OSTRICH 2010, 81(3): 173–178

Author Biographies

Sama Zefania
Department of Animal Biology, University of Antananarivo, Antananarivo 101, Madagascar
Razafimahatratra Emilienne
Department of Animal Biology, University of Antananarivo, Antananarivo 101, Madagascar
Patrícia J Faria
Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3US, UK
Michael W Bruford
Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3US, UK
Peter R Long
Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
Tamás Székely
Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
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Articles

Journal Identifiers


eISSN: 1727-947X
print ISSN: 0030-6525