On Christmas Island, what direct mechanism do the ants use to systematically eradicate keystone land crabs?

Answer

Swarming them and blinding them with formic acid spray until death from exhaustion.

When establishing a supercolony, the ants systematically kill tens of millions of native land crabs by swarming them and spraying them with formic acid until the crabs die from exhaustion or dehydration.

On Christmas Island, what direct mechanism do the ants use to systematically eradicate keystone land crabs?
speciesinsectantScientific nameyellow