The decline in insect populations throughout the world is a catastrophe we humans ignore at our peril. Far from being pests, insects carry the health of the planet on their tiny shoulders.
Story & Pictures: Andrea Abbott
When hard lockdown was decreed, I went on safari. The destination was my own ungardened property. As the weeks turned into months, my garden safari yielded a dazzling array of species I’d not previously noticed in our wild and tangled space. Aside from ‘new’ birds and amphibians, I met a vast suite of invertebrates I’d never noticed either. And, as my safari continued, it was those seemingly humble little beings that turned out to be the stars of the show.
Spiny flower mantids dressed in their floral best ambushed their unwitting prey; ghost mantids, invisible as lookalike dead leaves sprang to life when other beastlings appeared on the scene; plump caterpillars munched their way through foliage en route to their astonishing makeover; a kaleidoscope of winged beauties dipped in and out of flowers feeding on pollen and nectar; brazen robber flies sallied out from their perches to catch their prey in mid-air; and dragonflies and damselflies performed acrobatic stunts to outsmart their victims.
It was an energetic, eat- and-be-eaten world, like a mini Serengeti playing out in my own back yard. Even with all that devouring going on, there seemed no shortage of insects. And yet, there should have been a lot more. “Over 80% of all land animal species are insects,” says biologist and epidemiologist, Dr Marlies Craig, who is also Science Officer for the UN Intergovernmental Panel on Climate Change. “But, over the last 25 years, insect numbers have declined by 80% .” Meanwhile, the human population has doubled since 1970. More people equates to less space for wildlife. Driving that loss of habitat are factors like intensive agriculture, urbanisation, and the endless demand for resources. Add to this climate change, light and other pollution, and the indiscriminate, wide scale use of pesticides and it’s clear that insects are in trouble.
While a world with fewer insects might appeal to some, it would create an ecological catastrophe. For one thing, insects are at the centre of the food web.
As Dr Craig points out, 94% of vertebrates and 60% of invertebrates feed on insects at least some of the time, and in many cases exclusively.
Moreover, about a third of the world’s food crops are pollinated by insects, a job humans cannot do adequately.
Similarly, many herbivorous animals eat plants that insects pollinate.
But that’s not all. Seed dispersal, pest control, recycling of nutrients, waste management, the building up and enriching of soil – these and more are the good works of insects. They’re also effective weed eaters, if given the chance. “Plants are the producers so their job is to get eaten. When they’re not eaten, they’re not doing their job,” says Dr Craig. She explains that the majority of herbivorous insects are specialist feeders. This means they eat only one species of plant and won’t nibble even a close relative of that plant.
And so, what we plant in our gardens has a direct bearing on insects. Broadly speaking, a garden full of exotic plants will attract few insects. Few insects mean few other wild insect-eating animals such as birds. The exotic plants, uneaten and uncontrolled, are practically the only elements that will thrive to a point where they outcompete indigenous plants and become invasive.
To conserve biodiversity then, we must tolerate and accommodate insects. Instead of planting for show, colour and form, we should plant for life which involves planting a wide diversity of locally indigenous species – trees where it is correct for trees to grow (i.e. in historically forested areas) and grasses and forbs/wild flowers in places that were once grasslands. Pesticides and garden machinery like leaf blowers and trimmers that destroy little creatures have no place in living wild gardens. We need to welcome the sight of chewed leaves and of plants stripped bare and thrill to the sound of humming and buzzing – the sound of biodiversity.
Such an approach to gardening is in sync with the rewilding movement that’s gaining traction globally. Of the many rewilding projects from around the world, here are three examples.
At iSimangaliso Wetland Park in KZN, under the park’s previous CEO, Dr. Andrew Zaloumis, invasive plants and 14000 hectares of plantations were removed and the land allowed to recover. Today, it’s impossible to imagine the Eastern and Western Shores blanketed under commercial plantations. In place of those sterile zones are grasslands and wetlands where countless wild animals that had vanished from the region are again playing their part in the web of life.
In Sussex in England, the 3,500 acre Knepp Estate, once heavily-worked farmland, is proof of how a functioning ecosystem will recover where nature is given free reign. One of the most exciting triumphs was the hatching of three white stork chicks in May this year, the first time in centuries that wild white storks have bred in Britain. https://knepp.co.uk/home
On a smaller scale, lawns at Trinity College in Dublin, Ireland, have been pulled up to make way for wildflower meadows, this in response to growing public concern about the loss of wilderness. https://www.irishtimes.com/news/environment/trinity-college-lawns-dug-up-to-make-room-for-wild-flowers-1.4318693.
Rewilding doesn’t have to be a formal matter though. Anyone with a garden of any size can participate. All that’s needed to make a start is elbow grease and as many appropriate plants as will fit in the space. As those plants take hold, their attendant insects will arrive and in their wake, other species will pitch up too each filling a specific niche in the trophic cascade.
The importance of restoring wild places cannot be overestimated and has taken on new urgency in this time of plague. Covid19 has been a wake-up call for us all and scientists are warning of future pandemics that will be triggered by human interference in nature. On World Environment Day on 5th June this year, the United Nations put out this statement: The COVID-19 pandemic is a reminder of the gravity of biodiversity loss and of our unique interconnection with nature. Around 75 per cent of emerging infectious diseases are zoonotic, according to a report by the United Nations Environment Program (UNEP). Zoonoses are generated by viruses that jump from animals to humans. If ecosystems are degraded, the natural barriers between them are removed, thus creating conditions for wider spreads of viruses. Nature is sending us a message.
It’s a stark warning indeed. Our life support system needs healing. Insects are part of the medicine.
For more information on insects watch Dr. Craig’s YouTube video at:
Also, visit Dr Craig’s website: https://whatinsectareyou.com/
The UN’s full statement on preventing the next pandemic is at: https://www.un.org/en/un-chronicle/celebrating-and-safeguarding-biodiversity-prevent-next-pandemic-0