Males and females of many organisms differ in size. The explanation usually assumed, but rarely tested, for that difference deals with different roles in reproduction. However, these researchers have gathered preliminary data which indicates that the differences may often be due to evolutionary pressures dealing with survival rather than reproduction. The proximate goals of this project are to determine the relative contribution of evolutionary forces (primarily selection) that act upon reproduction compared to those that act upon survival. This project will also identify the nature of those evolutionary forces whenever possible. Differences between males and females of many organisms are of both basic and applied interest. Contributing to the understanding of the actual mechanisms that have caused these differences will be an important step. Currently there is a great deal of controversy about the relative roles of environmental and evolutionary forces as sources of differences between males and females. This project will provide important data that will help the debate.
