Symposium: Bateman's Principle: Is it Time for a Re-evaluation? January 2004, New Orleans, Louisiana

Society For Integrative And Comparative Biology, Herndon VA

Investigators

Abstract

Many areas in animal behavior, including evolution of a) matings systems (e.g. monogamy, polygamy); b) sexual selection (differences between the sexes that make one sex better able to compete for the other sex - e.g., the peacock's tail); and c) differences in male-female sexual behavior, have been profoundly influenced by a paradigm known as "Bateman's Principle". In 1948, Bateman, working with fruitflies, concluded that males compete for females - some males gain many matings while others do not; most females do mate. Moreover, male fertility increased with the number of mates, but female fertility did not. These results were ascribed to the fact that males produce billions of sperm, while females have relatively few eggs. Consequently, males should indiscriminately try to mate with as many females as possible, but females should be discriminating, sexually passive, and mate only with one "best" male. Bateman predicted that females should favor monogamy, and males promiscuity. Because males compete for females, sexual selection should be more important in males. These ideas began to be questioned when modern data showed that, in some species, these predictions do not fit. Some males may carefully choose among females and even refuse to mate with "inferior" females. Presumably monogamous females may actively seek copulations with multiple males, and thereby increase their fertility. This symposium brings together experts to evaluate which aspects of Bateman's Principles are still valid, and how modern data on male-female sexual behavior and its effects on fertility may impact our understanding of Bateman's paradigm.