Attacking Black Poison Ant
As Alros observed the ants, he is now sure of what they eat. Aside from the fruits, which he identified as Black Poison Berry, they seem to hunt other insects, though he did observe a small group of them being annihilated by a more powerful spider.
Aside from berries and other insects, it seem to eat almost anything, though it seem to prefer the berries and insect, while having some fruits as well.
As Alros observed them, he also thought of killing them. While doing so may seem counterproductive to his desire to have them as his monsters, one have to remember ants reproduce quickly.
Even big ants like the Black Poison Ant should adhere to this rules, or it would be hard for them to constantly replenish their numbers from his observations.