Stingless bees swarm for numerous reasons, which are all entirely different to the Honey Bees Swarms. Here are the two most common.
1. Drone Swarm/Mating Swarm When a queen dies, or a hive is split, one stingless beehive will be left queenless. This means that they need another queen. However, the reigning queen only ever allows one mated queen to be present in the hive. This means that all newly recruited virgin queens (see: ' Requeening Methods of Our Stingless Bees') will have to mate - and for that, they need drones (male bees) from other hives (for genetic diversity). Therefore, a mating swarm is necessary.
These swarms are usually only involve 10 to a couple of hundred bees. A gentle figure 8 flight path is common. They usually last only 3-10 days, and are identifiable by the drones resting on nearby objects with their antennae poking up like bunny ears. 2. Fighting Swarm If a colony of bees feels that they are strong enough to multiply, they can try to colonise a hollow in a tree, or telstra pits in suburban areas. Unfortunately, this can take many years. It is much easier to simply attack another, local hive - they already have an entrance structure, food stores, etc. Now all they have to do is overtake the worker bees, kill the queen, and replace her with one of their own. To do this, they must first attack the enemy colony, which they swarm. Fighting Swarms can have thousands of casualties.
These swarms usually contain many thousands of bees. They begin with a small cluster of a few hundred bees 'Checking the hive out'. Over a period of a few days, the numbers will rise significantly. Bees from opposing hives will grapple each other to the ground, two bees holding each other together in a 'death grip' - neither will survive. It is a battle of numbers. I you believe that your hive is being attacked, do not worry. This usually has no lasting effect on any hive.