Ants are social insects of the family Formicidae.

That would be called biological control of insects.

Solitary insects are alone and while social insects live together. My dad told me that one!

Insects that live on their own - as opposed to social insects.

Hugo A. Cordo has written:

'Insects that attack mesquite (Prosopis spp.) in Argentina and Paraguay' -- subject(s): Biological control, Insects as biological pest control agents, Mesquite, Phytophagous insects