Meeting Abstract

2.5  Sunday, Jan. 4  Testing an assumption of a model for the evolution of placentas BANET, Amanda I.*; AU, Arthur G.; REZNICK, David N.; University of California, Riverside; University of California, Riverside; University of California, Riverside amanda.banet@email.ucr.edu

Trexler and DeAngelis presented the first mathematical model for the evolution of the placenta. The model predicts that placentas will evolve in consistent, high resource environments. Imperative to the model is the assumption that placental species can abort a subset of developing offspring in low food conditions. Without this ability, the range of resource conditions in which a placental species can out-compete a non-placental species is extremely narrow. We test this assumption using two independent origins of placentation in the genus Poeciliopsis. We found no evidence that placental species abort offspring. Instead, placental species appear to be tethered to a brood once it is initiated and sacrifice body condition to maintain reproduction when resources are restricted.