Vulnerability of Pleurodema borellii tadpoles to an avian predator. Effect of size and density

CRUMP, MARTHA L.; VAIRA, MARCOS

HERPETOLOGICA

Herpetologists' League

Año: 1991 vol. 47 p. 316 - 321

0018-0831

Previous studies have identified two phases of a tadpole’s development during which selection should favor rapid growth and development: (1) small young stages and (2) metamorphic stages. However, no previous study has examined size selectivity of tadpoles by large vertebrate predators, such as a bird. In a series of field experiments using free-ranging great kiskadees (Pitangus sulphuratus) and four size classes of tadpoles of Pleurodema borellii, we documented that the bird greatly preferred the larger of two classes of tadpoles offered in a pairwise combinations. Given a choice between two densities of tadpoles, great kiskadees prefered to forage where density was higher. At both densities of tadpoles, the birds chose primarily the larger tadpoles