Insect Hotel gleanings...

From https://www.resilience.org/stories/2016-03-01/insect-hotels/

Insect Hotels Attract Beneficial Insects

Beneficial insects support biodiversity, the foundation for the world’s ecological balance. An insect hotel in your garden will attract these beneficial insects, offering them a space where they can propagate and hunker down for the winter. Encouraging biodiversity in the garden helps to increase ecosystem productivity.

Placing an insect hotel in the garden increases the chances that beneficial insects will naturally visit your garden. Also known as bug hotels, bug boxes, and bug houses, these human-made structures offer several benefits. In addition to their decorative qualities, they help supplement the increasing loss of natural habitats.

Although altered and heavily landscaped gardens can be beautiful, they often lack enough of the natural habitats needed to attract beneficial insects and encourage biodiversity. Placing insect hotels in your garden offers optimal bug real estate – the right kinds of habitats to attract these beneficial insects, increase their numbers, and reduce the need for pesticides, since these bugs offer biological pest control. A balanced ecosystem provides numerous benefits not just for the individual garden, but for the environment as a whole.

Benefits of Insect Hotels

1. Supplement the increasing loss of natural habitats
2. Encourage beneficial insects to help control pests
3. Stimulate biodiversity and ecological balance in the garden
4. Offer an opportunity for educating children about how balanced ecosystems work

Natural Pest Control

Welcoming beneficial insects and pollinators into your garden reduces or eliminates the need for pesticides. Poison kills weeds and pesky insects, but poison is not selective: it kills beneficial insects as well.

According to the USDA’s Natural Resources Conservation Service, three-quarters of the world’s flowering plants and roughly 35 percent of the world’s food crops depend on animal pollinators to reproduce, with more than 3,500 species of native bees helping to increase crop yields. By some estimates, one out of every three bites of food we consume depends on animal pollinators like bees, butterflies and moths, birds, bats, beetles, and other insects.

Insect Hotels: Purchase or DIY?

Different insects require different accommodations in which to thrive. Do a little research about the climate in your area before you decide what kind of insect hotel to buy or make. Each bug habitat performs a different function depending on the location’s climate. In cold climates, they offer a refuge for hibernation, while in warmer climates they function as dry nesting places during the wet season.

While there are many varieties of insect hotels available for purchase, building your own can be a relatively simple, fun, and educational DIY project you can do with children. Using a variety of found natural materials, you can build a bug or bee condo perfect for each type of insect you hope to attract.

Solitary bees and wasps seek places to lay their eggs, so they will be attracted to various-sized holes in wood. They also like to hide out in the open spaces in bamboo poles, which you can cut into small pieces. If drilling holes into wood, vary the sizes from 0.2-0.4 inches in diameter so other species will also fill those spaces. Not-so-nice wood works too: wood-boring beetles love rotting logs.

Reclaimed and repurposed materials such as old pallets, drilled logs, hollow bamboo poles, cardboard tubes, egg cartons, small stones, pieces of concrete and tile, pine cones, pieces of bark, found twigs, dead and rotting wood, hay, plant stems, and discarded planters are some of the kinds of materials that are perfect for constructing a habitat for your garden’s pollination and pest control workforce.

Where to Place the Bug Hotel

A bee hotel needs to be a high-rise to keep away ants, which love dining on bee larvae. Other bug boxes require sheltered but sunny spots surrounded by a variety of flowering and insectary plants (plants that attract and harbor beneficial insects).

Designers from all over the world have created insect hotels that double as works of art. Who knows, maybe you’ll be inspired to build a better insect house – and if all else fails, there’s always ready-made housing you can gift to your bug friends.

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From https://entomologistlounge.wordpress.com/2017/09/18/insect-hotels-a-refuge-or-a-fad/ 

Countless gardening stores and home furnishing stores sell insect hotels. Numerous blogs and websites have step-by-step manuals on how to build one yourself. All units are aesthetically pleasing which motivates well-intentioned buyers into adopting the concept. However, these insect hotels are often badly designed and they offer unsuitable home to the target insects. The warning sign of such designs is the unnecessary use of pine cones, glued snail shells, wood shavings and clear plastic tubes. Too many off-shelf insect hotels or build-your-own websites do not come with clear guide on maintenance, which is very important in ensuring the survival of the insects we intend to host.

Large insect hotels (aptly called insect condominiums) using wooden pallets are becoming very popular as individual or community gardening projects, sometimes to include non-insects such as frogs, toads and hedgehogs. In contrast, natural insect habitats occur as small separate nests, and large insect hotels pose risk of disease and parasitism to the insects inhabiting in high density inside. In fact, Rosita Moenen ^[1] observed that increasing number of badly-designed artificial nesting sites contributed to higher loss of (solitary) bees by parasitism.

Parasitism happens when kleptoparasites lay their eggs in tubes or cells occupied by bee larvae. Their larvae will hatch, consume the stored pollen and kill the bee larvae inside. Examples are parasitic wasps Melittobia acasta and Coelopencyrtus sp., and parasitic fly (Cacoxenus indigator) that attack red mason bees ^[1]. Insect hotels (especially large ones) make it very susceptible to parasitism. ^[1][2]. When not managed, the parasites will end up spreading to the rest of the insect hotels and will continue on for following seasons. In similar note, mould brings diseases to insects. It grows when moisture condenses and gets trapped in plastic materials ^[3] used in insect hotels as tubes and blocks. Lack of good roof/shelter on insect hotels, risking constant exposure to rain also contributes to mould growth.

Here is the right approach to insect hotels:

1. Insect hotel or insect refuge? Start by thinking which type of insect you wish to host. For example, in the Netherlands, ^[4] only three types of bees are tube nesters, namely red mason bees (Osmia sp), leafcutter bees (Megachile sp) and bell bees (Chelostoma sp). These bees occupy only small tubes between 2 mm to 10 mm in diameter. For majority that are ground nesters such as bumblebees, mining bees, plasterer bees (also known as silk bees in Dutch) and many types of beneficial wasps, an insect refuge is a more effective approach instead.

2. Be realistic – small is better: Assess your area where you plan to set up your insect hotel or refuge. Think small and have multiple units housing one species rather than a single large one that attempts to host an entire zoo, requiring potentially conflicting environments. For example, hosting frogs and toads require humid environment with partial shade, while bee hotels need to be dry and in full sun. After you gain experience, you can build and create a different unit for another species.

3. Choose responsible design: There are a number of good guides online written by entomologists and wild bee experts. Marc Carlton ^[3] and Werner David ^[5] have written extensively on right designs for bee hotels, in English and German respectively. For non-bee hotels suitable for lady bugs, lace wings and non-migrating butterflies, Melanie von Orlow^[6] has written a book with detailed manuals, available in Dutch and German.

4. Build your own, build it right: Sourcing your own materials gives you peace of mind that your insect hotel is made of natural, untreated wood and without chemicals such as varnish, paint and wood protectant that will repel insects. To promote sustainability, consider using recycled or natural materials from your garden. If tubes are drilled into blocks, tubes should be smooth without splinters. Good insect hotels should be built sturdy with solid back and roof/shelter to protect from rain.

5. Install it well: For example, bee hotels ^[3] must be positioned in full sun, facing south east or south, at least a metre off the ground, with no vegetation in front of it obscuring the entrances to the tunnels. It must also be fixed securely to prevent shaking and swaying from wind. 

6. Maintain and clean: This is the most overlooked part of having insect hotel. Taking care of insect hotel is just as important as building one. For example, bee hotels ^[3] should be inspected at the end of summer to remove and clean dead cells. This will prevent mould and mites that would multiply on the dead bees or larvae. Some experts recommend bringing occupied insect hotel into cool dry area such as garden shed during winter to protect the overwintering inhabitants from wind and rain.^[3] Without timely maintenance and clean-up, a once-occupied insect hotel may not attract a new batch next season.

7. Replace when it is time: Insect hotels can degrade naturally after two or more years because the material used is untreated. Change the nesting blocks or parts every two years to avoid build-up of mould, mites and parasites overtime.

Tips to make your garden an insect refuge:

1. Create sustainable nature: To encourage insects, especially pollinators, grow beneficial plants that that provide nectar and pollen. Choose native species ^[6][7] such as Lysimachia and Campanula flowers to promote natural biodiversity and avoid non-native plants.

2. An overly-manicured garden is not a refuge: Some non-migrating butterflies such as Papilio machaon overwinter as pupae attached to plants, so refrain over-trimming during autumn and spring ^[6]. Look out for ground nests of mining bees, bumblebees and beneficial wasps (German wasps and common wasps) before mowing or mulching your garden. It is easier to protect existing ground nests than to artificially create one.

3. Limit or no use of pesticides: Using pesticides (such as insecticides, fungicides and herbicides) will be counter-effective as it not only repels away or kill beneficial insects already living in your garden, it also disrupts the natural balance of a local ecosystem. Practise good housekeeping and maintenance so that you will never need to rely on pesticides in the first place. If such need arises, seek environment-friendly remedies or consult professionals instead.

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