Bee hotel

Definition

Serves the roughly thirty per cent of bee species that nest in cavities — mason bees, leafcutters, resin bees, scissor bees. Works with tubes from 2 to 10 mm at least 15 cm deep, facing south-east, kept dry and cleaned or replaced every year or two. Most commercial hotels offer only 8 mm tubes and miss the small specialists entirely.

Where the word gets used loosely

Bee hotels are frequently presented as the main thing a garden can do for bees. Around seventy per cent of species nest in the ground, and a patch of bare sunny soil serves more of them and costs nothing.

Bee records that discuss this

• Mason beesSolitary spring bees that build their nests out of mud, and the best orchard pollinators most gardeners have never noticed. A female mason bee works entirely alone: she finds a hollow tube, provisions a cell with pollen, lays an egg, walls it off with mud, and repeats until the tube is full. She will pollinate an apple tree several times more effectively than a honey bee while doing it, and she is almost incapable of stinging anyone.
• Yellow-faced beesThe bees that look least like bees. Yellow-faced bees are small, black, effectively hairless and marked with pale yellow or white on the face, and almost everyone who sees one assumes it is a small wasp. They carry pollen internally, swallowed into the crop and regurgitated at the nest, which means they have no pollen brushes at all — the feature people use to recognise a bee is simply absent. Seven Hawaiian species were the first bees anywhere to be protected under the United States Endangered Species Act.
• Red mason beeThe bee in your bee hotel. Osmia bicornis is the commonest cavity-nesting solitary bee in northwest Europe, the one most gardeners actually manage to attract, and one of the most effective fruit pollinators known — a few hundred females will pollinate an orchard acre as thoroughly as a honey bee colony of tens of thousands. It is also, for practical purposes, incapable of stinging anyone.
• Sharp-tailed beesCuckoo bees that specialise in leafcutters, and the females of which carry a striking piece of equipment: a sharply pointed, blade-like abdomen tip used to slit open a host's sealed leaf cell and insert an egg. The larva that hatches has enlarged jaws for killing the host's own larva, then moults into an ordinary-looking grub and eats the pollen loaf somebody else collected.
• Giant resin beeA very large east Asian megachild that has established across North America and Europe within two decades, and one of the few solitary bees anywhere to become a genuine invasion concern. It nests in existing cavities, seals them with resin, and has been recorded forcibly evicting native carpenter bees from their tunnels — which is unusual behaviour and the main reason it is watched.
• Blue mason beeA small mason bee with a striking sexual difference — the females are metallic blue-black and the males bright golden-brown, so unalike that they are routinely recorded as two species. It nests in small cavities and seals cells with chewed leaf paste rather than mud, which sets it apart from its relatives.
• Small scissor beesTiny, slender, cylindrical mason-bee relatives that nest in the narrowest cavities of any bee — beetle holes barely two millimetres across — and several of which provision their cells with pollen from a single plant genus. The harebell carpenter bee uses campanula pollen and nothing else, and males sleep inside the closed bells.
• Patchwork leafcutter beeThe leafcutter most gardeners actually meet, and the one responsible for the neat semicircular notches in rose and lilac leaves each summer. A female cuts an oval disc in a few seconds, flies off with it held beneath her body, and glues it into a thimble-shaped cell inside a hollow stem or a bee hotel tube.
• Resin beesTiny, cylindrical, near-black mason-bee relatives that gather sticky plant resin to seal their nests, and which specialise almost entirely on composites. They use very fine cavities, they have disproportionately large heads for their size, and a nest sealed with a shining resin plug is the sign they have been there.
• Dark beesSmall, dark, sparsely haired cleptoparasites that target the cavity-nesting megachilids — mason bees, leafcutters, scissor bees and resin bees. They are among the parasites that turn up in a bee hotel, and their presence indicates a host population large enough to be worth exploiting rather than a problem to be solved.

Guide records that discuss this

• Bee plants for a balconyBees will find a balcony several floors up, and containers can be genuinely productive. The constraints are watering, wind and depth, and the plants that handle all three are mostly Mediterranean herbs.