I built such bumblebee houses a few years ago with the kids. The flap is essential against a kind of flies that lay their eggs in the bumblebee nest and their caterpillars eats the nest.
Either the Queen or the others learn the usage quite fast. Sometimes next generation queens remember it in the next year
I built such bumblebee houses a few years ago with the kids. The flap is essential against a kind of flies that lay their eggs in the bumblebee nest and their caterpillars eats the nest. Either the Queen or the others learn the usage quite fast. Sometimes next generation queens remember it in the next year