Some honey bees build their walls from living bees

Some honey bees live behind walls made of other bees. The giant honey bee, Apis dorsata, builds a single exposed comb beneath a branch or cliff, then covers it with workers hanging together in several layers. Beneath that living curtain are the colony's developing young. There's no tree hollow enclosing the nest, and no wooden box supplied by a beekeeper. The workers themselves form the protective barrier between the brood and the weather, shielding it even during storms with heavy wind and rain. A nest without solid outer walls isn't necessarily a nest without shelter.

This is a different housing arrangement from the one familiar western honey bees usually choose. Those bees seek cavities, including hollow trees and spaces inside house walls. When a colony reproduces by swarming, its queen and a large group of workers leave together. They can gather in a temporary cluster while scouts search for a permanent home. That distinction matters: a hanging crowd of bees can be a colony between addresses, rather than an established nest with comb inside. The cluster is the travelling population. Once the bees settle into a suitable cavity, their new home can contain extensive comb, stored food and developing young.

The comb itself isn't a container with one big reservoir of honey. It's a structure divided into individual cells, and food storage is only part of its job. Worker honey bees produce building wax from their abdomens and construct comb downward from its attachment point. The familiar six-sided cells provide storage space for honey and pollen, as well as nursery space for young bees. In a typical nest, honey occupies upper areas, with pollen stores and brood below. A brood cell houses an individual developing bee. So the same structure serves as pantry and nursery, with separate cells holding very different contents.

Giant honey bees take that exposed construction to a substantial scale. Their single comb can reach 150 centimetres long and 70 centimetres tall, covered by a curtain of up to 100,000 workers. They're found across southern Asia, and their nesting sites include urban building ledges as well as trees and cliffs. A building can supply an attachment point without supplying an enclosed room. These colonies can also migrate seasonally to follow available nectar and pollen, leaving an empty comb behind when they depart. The wax structure stays attached to the old address. The population that built and protected it moves on.

Living in the open also puts workers within reach of hunting hornets. But the bee curtain doesn't simply sit there waiting to be picked apart. When a hornet approaches, workers flip their abdomens upward, with neighbouring bees joining in until a wave travels across the nest's surface. This behaviour is called shimmering. Observations show approaching hornets retreating when the waves begin, with stronger responses as more bees participate. The defence can repel a predator without workers leaving formation to fight it. That's what makes the hanging nest more than an unusual place to find honey: its outer covering is a coordinated workforce, protecting the colony by moving together.