KIN RECOGNITION IN ANURAN AMPHIBIANS

Anuran amphibians have emerged as model vertebrates for the study of kin recognition mechanisms. Larvae of most species reported to date discriminate between kin and non-kin, but anuran kin recognition systems show substantial interspecific variability. The ability to discriminate between kin and non-kin incorporates some form of learning in most, if not all, anuran species studied. Kin recognize one another through chemical cues which may incorporate environmental, genetic and maternal factors. The development of kin recognition is influenced by the rearing environment in some species, but in others, social factors have little effect. Kin recognition is context-dependent, however, and the failure to discriminate between kin and non-kin in laboratory tests may reflect artificial testing circumstances rather than differences in kin recognition abilities. Kin recognition mechanisms may have been selected because they enhance opportunities for cooperation among close relatives, but also might result incidentally from other life history processes. Larval growth and maturation may be accelerated when tadpoles recognize and preferentially associate with siblings. Moreover, kin recognition abilities sometimes are retained through metamorphosis. In natural populations, toads rarely mate with their siblings though close kin are readily accessible as mates. These findings suggest that kin recognition may facilitate optimal outbreeding. © 1992.