Solitary bees are important pollinators and will lay their eggs inside the bamboo tubes along with balls of pollen. They cap off the end with leaves and chewed bark. The grub hatches inside and feeds off the pollen before emerging as a new bee! Other insects such as ladybirds may also overwinter in the tubes. Hang the insect house from a wall, or stand on a shelf ideally around 1m from the ground.