They are reddish ants and live high above in treetop nests they build and belong to the ant genus Oecophylla (subfamily Formicinae). A giant weaver ants nest may look like it is damaging the leaves and branches of a tree. But weaver ants actually protect the tree and are like miniature bodyguards for the tree. They have “sweet tooth” and have a strong chemical in their bodies called formic acid, which they used to protect their nests. Actually they are harmless ants if you dont disturb their habitat.
Just be careful when you are taking a stroll under the many trees in the Botanical Garden.