Why is bhramari devi the goddess of black bee?

Once there was a demon named arunasur who was blesses by god brahama that he would not be killed by humans,gods,celestial beings and any form of life that would be two or four footed.these boons granted by god brahama made arunasur invincible and unprecedented,as the result he defeated all the gods and took over the throne of heaven he also captured forces of nature chiefly fire,water,air,earth etc.As the result all the gods became exasperated and requested goddess durga to save their lives pacified by their pleading Words goddess promised them to kill arunasur Goddess durga approache'd arunasur and challenged him for the battle ,infuriated by goddess's challenge arunasur attacked her ,as he could not be killed by gods,humans,four OE two footed beings so to respect the Words of god brahama goddess turned herself to thousand of swarms of bees (called as brahmri in Sanskrit)goddess repeatedly stung arunasur and administered poison in his body leading to the death of demon.After this incident goddess durga was called as bhramari devi due to her incarnation in brahmar or black bees to slay demon arunasur.