Hotels are usually built for travellers, but some are designed for creatures no bigger than your thumb. Scientists and conservationists have spent years creating these miniature refuges for wild bees in the form of small nesting structures fitted with narrow tunnels that mimic the hollow stems and cavities many solitary bee species naturally use to lay their eggs. Hoping they could provide additional nesting spaces in increasingly urban landscapes, Canadian researcher J. Scott MacIvor installed 200 bee hotels across a city and monitored them for three years. What began as a simple conservation experiment soon uncovered an entire hidden community of insects, prompting researchers to rethink how artificial nesting sites influence pollinators and urban biodiversity.Why scientists are building