The purpose of this study is to clarify the interaction between the formation mechanism of the distribution pattern of ants supported by pheromone signals and the regulation mechanism of task-allocation in collective behavior of an ant colony. In this paper I design two types of ant colony model focusing on pheromone signals and the sensitivity of ants, and analyze simulated behaviors of the models. First, I design three foraging models (trail, attraction and desensitization models) composed by ants with different sensitivities to recruit pheromone. Among them, the desensitization model composed for ants that change their sensitivities in response to environmental information around them always shows the best foraging efficiency, stable recruitment pattern and balanced allocation among subtasks. In the second, I design a task-allocation model composed for ants carrying out foraging and mound-piling tasks using independent signals for each task. The results indicate that weak interference occurs between both tasks.