I know that I've touched upon the subject of worker ants before, but aren't they fascinating? There were quite many of them where I was drawing, out in the finest of May (ink on paper, electric colours later). This one looks a little mean.
The insect assailed by the ant might be a Lesser Green Chequered Cogwheel Bug. (Now they exist.)
Poor thing. It is difficult to tell a Worker Ant that you have rights (or exist at all, other than in culinary terms) if you're not an ant and a worker. Ants are social, ants are good, ants care for other ants. But not for little green bugs.