That way each female could adjust the number of eggs that she would lay, her objective being to prevent over-exploitation of the environment.
Domestic sheep are a counter example.
If not herded along, sheep will crop all edible plants beyond recovery. In 1966 George Williams published a book that initiated the demise of the notion that organisms evolve by group selection. This depends upon the rate at which whole groups fission and become extinct. Proper models show that both rates need to approach the rate at which individuals are born and die. For whole groups, such rates are orders of magnitude beyond realistic.