TIMING OF PARTURITION AS A MATERNAL CARE TACTIC IN AN ALPINE LIZARD SPECIES.

Lack of ability to buffer postparturient offspring mortality risks may put a female under strong selection to time the birth of her young with benign environmental conditions. We provide support for timing of parturition as an adaptation in Tasmanian snow skinks (Niveoscincus) by demonstration of (1) ongoing selection against poorly timed parturitions, (2) retention of full-term young through episodes of unfavorable conditions, and (3) phylogenetic shifts from autumn to spring parturition in taxa where costs of autumn parturition are expected to be relatively higher. © 1998 The Society for the Study of Evolution.