"Attempts at human habitation along the Trash Coast have always failed, because spiderants overwhelm anyone who tries to live there. The bandits managed it, though, by placing a Queen Spiderant Abdomen in the middle of their camp. I want you to take an abdomen from a rival Queen, then replace the bandits' with that one. Let's see if the spiderants will do our dirty work for us."
Collect a Queen Spiderant Abdomen and swap it for the bandits'.
Go to point number one on the map. Get Queen Spiderant Abdomen killing the Queen Tarantella.
Go to the center of the bandit camp (point two on the map) and plant your abdomen on a special pillar. Kill all the Spiderants. The last kill the King Aracobb.
"Wow! That was even more successful than I'd hoped! I don't know if that's an easier way to keep the bandits under control, but it's sure as hell more fun! Here's your reward for a job well done."