I. Introduction
Swarm intelligence (SI) as classical bio-inspired computational intelligence draws inspiration from collective behaviors exhibited by animal groups [1]–[7]. Generally, each SI paradigm is a population of unsophisticated individuals that possesses a collective intelligence. The individuals within such population can interact locally with their environment to cause coherent functional patterns emerge. It is worthy noted that in most SI algorithms, their populations are usually blindly determined by using a fixed size, which is a departure from the life-cycle mode of evolutionary mechanisms of biological populations.