The ants will climb up and get into the figs so you'll need to fit a grease band to the trunk to stop them. If you want rid, red ants can be killed by sprinkling fine ground polenta or semolina. The workers take it back to the nest, feed it to the queen who is unable to digest it and she dies. The theory is no queen - no nest. Haven't found it to be successful on black ants though so you'd have to use a proprietary product.
