Stingless Bees, spotted in the Queen Sirikit Botanical Garden (fig.) in Chiang Mai, making tubular entrances to their nest −open mud-tubes that form straight chimneys above the nest's holes− in order to raise the entrances above the surrounding vegetation.

Thes chimneys are made from wax mixed with resin and gum, while some species add mud collected by worker bees to it (fig.).