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How to nurture an insect-friendly garden


Insect-friendly garden

Lars, Unsplash

The fate of Earth’s tiny creatures is tied to our own and should concern us all. Here’s what we can do at home to help insects on the decline due to man-made forces including pesticides, habitat destruction, climate change and more.

Creepy, crawly, tiny and mostly unobtrusive, insects have mostly taken a back seat in the public eye when it comes to threatened species. While the focus of conservation efforts has been on glamorous mammals like snow leopards and polar bears, insects are going extinct eight times faster than their vertebrate cousins.

More than 40 per cent of insect species are at risk of annihilation in the coming decades, according to a review of 73 reports on declining insect populations in the journal Biological Conservation. Those most in decline are butterflies, moths, dung beetles and hymenoptera (the order which includes bees, wasps and ants). Critically endangered aquatic insects include mayflies and dragonflies. The researchers blame intensive agriculture, habitat loss, synthetic pesticides and fertilisers, and to a lesser extent, climate change, pathogens and introduced species.

“Along with decomposition, breaking down plants, dung and other things in the environment, and recycling nutrients, [insects] provide food in the middle of the food chain. If we didn’t have insects the system would collapse. We can’t live without them.”

Many scientists believe we’re experiencing a “sixth mass extinction”, a loss of wildlife unparalleled since the dinosaurs, caused by human overpopulation and activity. When it comes to declining insects, American entomologist, Dr Jeff Pettis, believes pesticides, which contaminate land, water and air, are the single biggest factor. Proof of insect sensitivity to pesticides, a 2015 UK study found exposing wasps to a sub-lethal dose (100 parts per billion) of pesticide reduced offspring production by about 20–25 per cent.

Might of the mini beasts

Tiny critters play a goliath role in supporting life on earth, Pettis says. Proof of their significance, “There are more insects in the world than any other living thing except micro-organisms like bacteria and fungi,” he says. “Along with decomposition, breaking down plants, dung and other things in the environment, and recycling nutrients, they provide food in the middle of the food chain. If we didn’t have insects the system would collapse. We can’t live without them.”

Predatory insects like spiders and lady beetles also keep “pest” critters in check. However, one of the most crucial roles of Earth’s mini beasts is pollinating our food supply. A third of the world’s food comes from crops requiring, or benefiting from, insect pollination, Pettis reveals. “But it’s the very important third where most of the nutrition comes from. All fruits, nuts and vegetables have to be pollinated by some kind of animal. Bees carry most of that weight.”

“Along with decomposition, breaking down plants, dung and other things in the environment, and recycling nutrients, [insects] provide food in the middle of the food chain. If we didn’t have insects the system would collapse. We can’t live without them.”

Pettis, who has been studying bees for more than 30 years, recently contributed to an intergovernmental analysis: Assessment Report on Pollinators, Pollination and Food Production. It notes that pollinating insects are critical to the food supply and habitat of other species, given 90 per cent of wild flowering plant species depend on pollinators.

Bees ‘n’ us

Bats, birds, butterflies, moths, beetles, wasps, flies and other creatures are involved in pollination, however bees do the lion’s share. The report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), found over 90 per cent of the world’s leading crop plants are visited by bees. This compares with about 30 per cent of flies and 6 per cent of other insect taxa. Bees additionally provide honey, beeswax and medicinal products like propolis.

Our association and dependence upon honeybees goes way back, and has only grown, Pettis says. “There are cave paintings where they show people robbing honeybee hives. Humans rely heavily on them in agriculture systems, but humans have always relied on them.”

While most of us are familiar with the European honeybee (Apis mellifera), there are at least 20,077 bee species globally, according to the IPBES report. The vast majority are wild bees, whose contribution to pollination is vastly underestimated.

Within Australia, there’s an estimated 2000 species of wild bees, according to Terry Houston’s A Guide to Native Bees of Australia. One example is the blue-banded bee. It performs “buzz pollination”, which is valuable in pollinating blueberries, kiwi fruit, chillies and nightshade crops. In buzz pollination, something honeybees don’t practise, bees buzz and vibrate the flower to make it release more pollen, Pettis explains.

Create open spaces like paths, meadow areas and ponds. Butterflies need the warmth of the sun and like flying over sunny, open spaces.

“There are a lot of different body shapes and styles out there,” he says. “This includes fly- and wasp-mimicking bees. Sometimes the wild ones have a certain characteristic and emerge in the environment exactly when a certain type of flower blooms. There are certain associations that are really one-to-one, like an unusual flower type, and nothing else will pollinate it. Why are there so many types of bees? Because there are so many different types of flowering plants. And bees and flowering plants go together.”

As a group, bees make exceptional pollinators because of their hairy bodies. “When they visit the flower, pollen gets all over their body and they move to the next flower,” Pettis says.

Due to their sociability, European honeybees build communal hives that allow them to be managed by humans. However, the majority of wild bees are solitary. “The wild bees are more threatened because no one’s looking after them and you can’t manage them,” Pettis says. “People plough up fields or build houses or parking lots and destroy the nesting sites, and then pesticide use kills off other bees. Often it’s a single female that’s trying to establish a nest and keep the system going. If she gets a little bit of pesticide in her pollen then she’s gone for the year. How do you save them? You save them by saving, and not disturbing, the environment.”

Lessons from the bee hotel

According to Julia Common, co-founder of non-profit organisation Hives for Humanity and head beekeeper at the Fairmont Waterfront hotel in Vancouver, the key to helping bees lies in greening our cities, sustainable agriculture and banning pesticides. Vancouver has already made huge strides towards this.

One of the world’s most green and bee-friendly cities, Vancouver has banned neonicotinoids (pesticides toxic to insects), established green pollinator corridors and changed by-laws to allow urban beekeeping, Common says. Bees require continuous expanses of greenery and places of forage. “Honeybees can fly 3-4 miles. The indigenous ones can go only 100 to 400 metres. They need lots of snacking,” she explains. Surprisingly, Common says cities are good environments for bees, explaining: “They have stable flowers that are watered.”

Providing inspiration on how to care for our fuzzy friends in style, Fairmont Hotels, the first luxury hotel brand to implement an onsite bee sustainability program (in 2008), has more than 40 apiaries and wild bee hotels in its properties around the world. At the Fairmont’s Waterfront hotel in Vancouver, and nearby Château Whistler, cute hive boxes and twiggy bee hotels on the rooftop gardens provide sanctuary for European honeybees and wild native species. Here, the honeybees (currently numbering around 250,000 at Fairmont Waterfront Vancouver) and their wild cousins forage on organic bee-friendly flowers like lavender.

Avoid buying plants where the seeds have been pesticide-treated. “For the first year or two those bee-friendly plants have pesticide in the plant itself. The bees feed on the nectar and pollen and there’d be a little bit of pesticide there. It will weaken them.”

The average life of a honeybee colony has declined dramatically, Common says. “In the old days a bee colony would go forever. The problem for bees is they need more and more nutrition to fight pollution effects. The chemicals are sub-lethal. What we find is our colonies don’t thrive. The babies don’t develop properly, what’s called ‘brood diseases’. It can be stress, bad nutrition, lack of home. They become way more susceptible to disease.”

Climate change also affects bees. “The temperature needs to be about 15°C for nectar to flow,” Common says. “Above 30°C there’s no moisture and flowers can’t produce nectar.” She suggests helping weak bees in summer by offering them sugar diluted in water.

A concerted effort is needed to save bees. Thus, education is important. The Fairmont’s Pollinator Menu, which features more than a dozen culinary ingredients that depend on bees (including scrumptious honey and berries from the rooftop gardens), remind us of some of the foods we’d potentially lose without pollinator species. Visitors can browse the bee information displays or take one of the educative tours offered by volunteers under the hotel’s Bee Sustainable program.

Bee-friendly habitats

The best ways to help bees in our garden are to avoid using pesticides and provide a habitat and forage for them, Pettis says. “We need to go back to more sustainable farming and gardening.” This includes using natural fertilisers and materials and digging less.

“About 70 per cent of solitary bees live in the ground,” he says. “Typically, a female digs a little hole in the ground and has a nest and about five offspring. The males are somewhere in the picture but they don’t play an important role. They have to have a certain type of ground, whether its clay or sand. There are a lot of different soil types they like. If the soil has been disturbed or ploughed up, then they can’t nest in it. That’s why habitat destruction is so huge. There’s nowhere for them to live. They need undisturbed natural areas.” The other 30 per cent of solitary bees live in rotten wood like old trees and logs, and inside decaying woody stems and old vegetation, Pettis says.

Building your own bee and insect-friendly haven

As the saying goes, “build it and they will come”. Here’s what you can do at home, according to the experts.

Create a habitat

– Increase undisturbed, untilled areas. Establish wildflower meadow areas or perennial beds. Hold back on mowing.

– Reduce impenetrable landscaping such as concrete paving.

– Leave decaying stubble in over winter. Try planting around it.

– Keep a few rotten logs in the garden.

– Buy or make your own bee hotel with hollow wooden, cardboard or bamboo tubes and sticks for wild bees to nest in.

– Build a pond with waterlilies and cattails (useful as egg-laying sites) and other aquatic flowers to help foster populations of dragonflies and other water-based insects.

– Make hollows with rocks and earth for insects to shelter in.

– Create open spaces like paths, meadow areas and ponds. Butterflies need the warmth of the sun and like flying over sunny, open spaces.

– Create a small shallow water pool for insects to access water in hot months.

Go organic

– Avoid using pesticides, fungicides, herbicides and other chemicals.

– Avoid pesticide-treated wood landscaping.

– Learn about and practise organic sustainable gardening.

– Avoid buying plants where the seeds have been pesticide-treated. “For the first year or two those bee-friendly plants have pesticide in the plant itself,” Pettis says. “The bees feed on the nectar and pollen and there’d be a little bit of pesticide there. It will weaken them.”

Stock the pantry

– Bees need pollen and nectar; butterflies also feed off flower nectar plus tree sap and organic matter.

– Design your garden to bloom through the seasons. “Mid-summer and early autumn is the critical time,” Pettis says. “There’s lots of stuff in the spring. Below temperatures of 10-12°C, honeybees cluster inside the hive, surviving off the honey they’ve stored. The wild, solitary bees usually burrow into some kind of protection and hibernate. If the temperature’s too cold, they can’t fly.”

– Foster biodiversity in your garden.

– Let your veggies go to seed for additional flowers.

– Avoid conifers, modern hybrid flowers and lawn — they don’t offer much for bees and other insects.

– If you live in a unit, add flowering potted plants to your balcony, window, or shared communal space.

Favoured plants

– Bees love all flowers in the mint (Lamiaceae) family, including bee balm, hyssop, rosemary, salvia, sage, catnip, lavender, thyme, oregano and basil, Pettis says. “Any kind of good nectar plant is really valuable. There are all these kinds of things that are rare, but bees will find them.”

– Bees love echinacea, butterfly bush and borage (known as bee bush or bee bread).

– Indigenous natives like banksia, bottlebrush, tea tree, eucalyptus and some wattles produce lots of pollen or nectar.

– Daisies. Bees enjoy ranging on the shallow flowers. Butterflies like the flat tops for landing on.

– Flat-topped, umbel-shaped flowering plants like dill, coriander, parsley, fennel, angelica and Queen Anne’s lace. Beneficial predator insects like ladybirds and hoverflies favour umbels for landing and sheltering sites. Bees thrive on the flowers.

– The flowers of Alliums (the onion family) and fruiting trees.

– Dandelions, buttercups and clover.

– To attract butterflies try butterfly bush, verbena, salvia, wallflower, nettle, passionfruit and native grasses. If you want butterflies, you have to help caterpillars (few survive to become butterflies). Give them hiding places.

– Night-blooming flowers support moths.

Educate others

– Use your insect-friendly garden as a conversation starter to educate the neighbourhood.



 

Linda Moon

Linda Moon is a freelance feature writer reporting on health, travel, food and local producers, work, parenting, relationships and other lifestyle topics. Her work has appeared in International Traveller, Voyeur (Virgin Airlines magazine), Jetstar Asia, Slow Living, Traveller, Domain, My Career, Life & Style and Sunday Life (Sydney Morning Herald), Sprout, NZ Journal of Natural Medicine, Nature & Health, Australian Natural Health, Fernwood Fitness, The New Daily, SBS, Essential Kids, Australian Family, Weekend Notes, The Big Bus Tour & Travel Guide and more.

Based in Katoomba in the Blue Mountains, Linda is a qualified and experienced naturopath, spa and massage therapist and a partly trained social worker.

Her writing interests focus on health, responsible consumerism, exploring beautiful places and the quest for a fairer, healthier and happier world for all.