How to make and run a bee hotel

Bee hotels have become so popular you can buy them at craft markets and even $2 shops.

But there's a growing body of research suggesting that large, ornate, mass-produced condominiums could actually encourage predators and diseases, making bees more vulnerable.

In case you've missed it, a bee hotel is a structure you stick in your garden, with the idea that it gives native solitary bees a place to next, rest and breed. Honey bees and native social bees build their own nests and live in hives.

But even the most well designed hotels can become unhealthy homes if not managed properly.

And the ones working well often attract as many wasps as bees — and that's OK because we need them too, but maybe we should call our contraptions "insect hotels" instead. Or, as the sign reads on one fancy specimen in an English beer garden: The Grand Bug 'n' Pest Hotel.

How to avoid your bee hotel becoming a hoodlum hangout

The thinking is that, while a certain level of predation by pests and parasites is normal in nature, large, mass-produced bee hotels bring unnaturally high numbers of insects together, making it easier to be found by parasitic wasps — plus ants, mite, and spiders. A sort of bee smorgasbord.

"As soon as you start concentrating animals you will attract parasites," says Katja Hogendoorn from the University of Adelaide.

"It's best to have a few smaller hotels scattered around a garden — just 20 metres apart will do."

Also, one-size-fits-all nests are too uniform because different bees need different nest sites. And, to make matters worse, some designs glue the nesting material into place, so it can't be cleaned out — an essential task for keeping pests and diseases in check.

It turns out that bee hotels are far from "set and forget".

Think about building a bee restaurant instead

If a hotel is too much work, you could consider going into the bee restaurant business instead.

Dr Hogendoorn believes planting food for bees is even more important than hotels.

"I don't promote bee hotels because bee restaurants are much more important," she says.

"The key is definitely local native plants — ones with nectar-producing flowers, such as banksias, melaleucas, grevilleas and eucalypts."

Daisies, fan flowers (Sscaevola) and pea flowers are also good.

Kit Prendergast, a PhD student and native bee scientist at Curtin University, promotes bee hotels because it helps people understand bees, but she agrees with adding native plants too.

"Even native gardens can't replace bushland — you always find more bees in bushland, so we need to keep that as much as possible — but second best is improving gardens [by adding native plants]," she says.

What makes a good or bad bee hotel

If you're looking to buy a pre-made hotel, here are some features to avoid:

• No backing board to hotel, leaving insects exposed to wind and rain
• No protective roof, or roof without overhang
• Bamboo sticks all the same (large) size — holes more than 1cm across won't get used
• Bamboo cut so the nodes (the "walls" within the stem) are at the front, blocking entry
• Splinters and rough edges inside holes — these can rip fragile wings
• Shallow (less than 15cm) nest tubes — some bees lay female eggs at the back and male at the front of a 10-15cm tunnel; if it's too short you'll only get males, and no future egg-layers
• Plastic or glass tubes — these hold too much moisture

How to build your own bee hotel

There's no need to spend a lot of time and money on a hotel; an empty plastic soda bottle with the bottom cut off (this forms the front) and the lid left on (to form the back) can be crammed with a range of different nesting material and lodged in a warm, sheltered, east-facing spot at about eye height.

As with anything in nature, diversity is best, so use a mix of these materials:

• Fennel stems: strip foliage from main stem and cut into lengths with at least 10-15cm of pithy stem between joints. Soft stems of lantana, grapevines and hydrangeas are also good.
• Bamboo hollows: choose mostly thin sections of bamboo, up to a pencil-width across, cut into lengths. Pick stems that have 10-15cm between joints, then cut just below one joint so there is a good long hollow section available to the bees.
• Drilled logs: ALWAYS use untreated wood. Cut into blocks or logs about 20-30cm long, then drill holes at least 10cm deep into the cut end, using a range of drill bits from 3-8mm. Space the holes around 2cm apart. It can be a good idea to put liners of rolled cardboard in the holes to make it easier to clean out the hotel when your baby bees have left — like new sheets for the next guest (see housekeeping, below).
• Clay-packed pipes and blocks: blue-banded bees make nests in the soil, so you can replicate this by packing clay or clay soil into PVC piping or concrete blocks. Using a stick about 8mm wide, poke holes into the clay around 10-15cm deep. Blue-banded bees like to stick together, so provide space for at least 10-20 individuals.

Other building tips:

• Put a sloping roof on the hotel with a generous overhang. A little bee landing strip would be appreciated, too.
• Avoid composite materials such as cardboard, particle board or chipboard for the frame, as these disintegrate in wet weather.
• Individual bee species have very specific preferences. There are more than 1,600 different bee species in Australia. Luckily, they're generally grouped in families and you can check online to see what lives in your area.

Bee hotel housekeeping and room service

Bees are seasonal creatures, only active in spring and summer, with the adults dying off in autumn and winter.

Resin bees lay their eggs with a stash of food then seal off the end with some resin. Some will hatch the same season — you'll see a hole in the resin seal — and over winter it's important to clean out old nesting material to reduce the risk of diseases.

However, some larvae may still be dormant inside over winter. To protect these, you can put the nesting material in a shoe box with a hole cut in the lid, store in a dry place, and the insects will emerge when they're ready.

This is another good reason to use cardboard liners in drilled holes — the lining tubes can be stored in the box instead of the whole block of wood.

Fast facts about native bees

• There are more than 1,600 native bees species in Australia. Only 11 are stingless (and these can bite).
• They come in a range of colours — yellow, black, red, green or neon blue. They can be fat and furry or sleek and shiny.
• They range in size from 2mm to 24mm. The world's smallest bee is the Euryglossina Quasihesma (2mm) found in Queensland's Cape York area. The biggest Australian bee is the great carpenter bee (24mm) found in the tropical north and northern NSW.
• Most native bees live alone, but the stingless bees build group hives. Stingless bee honey, or sugarbag, can be tastier than "regular" honey, but the bees produce much less — about four cups a year. Stingless beekeeping is becoming more popular in Australia's north.
• Blue-banded bees (Amegilla) are 11mm long and one of Australia's favourite native bee species. They nest in shallow burrows in the ground.
• The neon cuckoo bee (Thyreus nitidulus), with glittering metallic blue spots, lays its eggs in the nests of blue-banded bees, which it mimics.
• Some plants "lock up" their pollen, only releasing it when vibrated at the exact frequency of native bees. These plants can't be pollinated by honeybees, which don't vibrate this way. (Tomatoes are also "buzz-pollinated" this way, so native bees can improve tomato crops.)
• Leafcutter bees line their nests with perfectly precise circles cut from plant leaves.
• Commercial honeybees (Apis mellifera) were introduced from Europe in about 1822.