Decline in important pollinators globally - and locally
In April 2025 we were fortunate to enjoy a presentation by two excellent speakers, John Catton, who specialises in Bees, and David Dennis who is expert in Moths and Butterflies. Both John and David discussed how rapidly insects have declined since the 1970s and the reasons for this catastrophic decline. When did you last have to clean your car windscreen, sticky from dead insects?
This decline has been well documented. According to David, ‘the UK has the best historical information about trends because of amateur and professional recording over many years. Since the 1960s we how have 43 million records for Moths and 17 million records for Butterflies. These demonstrate that since the 1970’s moths have declined by over 30% and butterflies by around 20%. The "Bugs Matter" survey in the UK ‘has revealed a significant decline in flying insect populations, with a 65% decrease in Scotland and a 62% decrease in England between 2021 and 2024. This alarming trend is mirrored in other scientific surveys of butterflies and moths, indicating a widespread and concerning drop in insect numbers.’
John pointed out that flying insects emerged about 400 million years ago which coincided the Earth’s first land plant life with which they have had a symbiotic relationship ever since.
David states ‘Insects are vital for the health of the planet not just as pollinators but also at the bottom of the food chain for birds, bats, rodents etc.’ He listed reasons for the decline include loss of habitat; the use of pesticides; nitrogen pollution from burning fossil fuels and from artificial fertilisers; and climate change. According to Tess McClure and John Greenfield in the Guardian ‘even in nature reserves that are largely protected from human touch…. we are also beginning to see huge drops in the populations of other animals – such as birds – that depend on insects as food’. John showed slides of people having to pollinate crops by hand when insects were wiped out by the use of pesticides.
In discussing the effects of climate change, John acknowledged that there have always been fluctuations in climate including five or six major ice ages throughout which insects were able to adapt and diversify. What is different now is the rate of climate change which is making it difficult for them to adapt quickly enough and our erratic weather patterns which affect their food sources. David observed that ‘species are moving north throughout the northern hemisphere to maintain their preferred temperature range: in the 1970s at 1km per year, in the 2020s at 3km per year, and it’s still accelerating. For butterflies and moths in the UK this means that southern species are now being found as far north as Scotland. At least one butterfly (Mountain Ringlet) is running out of high enough mountains in the UK and will probably go extinct here. New species are arriving from Continental Europe. Since 1900, there have been 55 extinctions with 137 new arrivals almost all of which are moths.’
What can we do? In the light of this discouraging situation, it would be easy to despair and to think that there is little we can do as individuals. However, both speakers highlighted the amount of land that we humans use as gardens and strategies for making our gardens more insect (and other wildlife)-friendly which would have positive effects on their survival. John pointed out that our gardens alone cover nearly half a million hectares of the UK which is more than all of our nature reserves. They can be an interconnected network of insect-friendly habitats. Insects need food, shelter and water for survival. Strategies to provide these by making our gardens more insect friendly include
making wilder gardens, letting the grass grow longer, following No mow May: ‘No mow May is one of the most successful recent environmental campaigns in the UK, intended to provide more habitat to bees, butterflies and other invertebrates during a key part of their lifecycle when they are emerging from a cold, hard winter. But it doesn’t have to be only May. Letting grasses grow uninterrupted, particularly where native wildflowers thrive, can be a big boost for insects.’ Guardian
planting wild flowers; ‘One of the best things you can do for insects is cultivate native plants, says Prof Douglas Tallamy, an entomologist at the University of Delaware. Local insects have evolved alongside local plants, and adapted to specific bloom shapes or leaf textures – many bees, for example, will only visit a single type of flower, even if others are growing nearby. Imported ornamental species and foreign plants often don’t work as food or shelter for local species – by installing native plants, you can help insects get the food they need.’ Guardian.
‘Sometimes, all a vacant plot, neglected berm or empty lot needs to boost its biodiversity value is seeds. Researchers from Poland recently found that patches of wildflowers in cities can be just as good for insects as natural meadows. By protecting and growing those patches, “we can alleviate the hostile environment of urban space for wildlife”, the researchers wrote. A number of NGOs distribute free native wildflower seed packs. You can even buy (or construct) your own sprinkling system: put a mix of seeds in a spice shaker, and carry it to sow flowering species in neglected spots of green.’ Guardian.
having a succession of flowering plants; John states ‘With the exception of honey bees, insects do not store food thus need a continuous source of nectar and pollen throughout their lifecycles so ensure there are different plants in flower from early spring to late autumn. Some examples of plants when bumble bees and solitary bees most need your help are Spring – snowdrops, crocus, mahonia, primroses and pulmonaria and Autumn Sedum, Michaelmas Daisies, Ivy and Golden Rod.’ However, John says to select plants that you like since research has shown that they don’t necessarily have to be native. Other recommendations from John include:-
leaving untidy patches in the garden; As well as sheltering from extreme heat and cold insects need places to build nests, lay eggs and hibernate so encourage them by leaving and untidy corner of your garden creating log piles.
delaying tidying up/cutting back the dead stems of larger hollow perennials until spring; leave seed heads- they provide hibernation sites as well as looking statuesque on a frosty winter’s day.
buying or making a bee hotel or a lacewing home: (could be as simple as drilling 6mm to 10mm holes into old wooden posts).
building a pond, however small, (or even providing a shallow dish of water with some stones in it): The way our climate is shifting water is a vital necessity for gardeners as well as insects. From a terracotta plant pot saucer half filled with pebbles and kept topped up with water, to a wooden butt or old sink, or all the way to digging a pond in your garden. Remember though to have access points for insects to drink from – aquatic plant leaves / rocks – and egress ramps for those small mammals which may accidently fall in.
putting away pesticides: By planting your garden with biodiversity in mind, you will create a “naturally balanced ecosystem”, a space where the beneficial insects keep the destructive ones in check. By using pesticides, you kill the good guys along with the pests. It’s inevitable you’ll find aphids on your broad beans or roses, but given time lacewings, solider beetles, hoverfly lave and even wasps will find and eat them.’
swapping moth bombs for wasps: ‘Clothing moths are a huge pest in many households, chewing through winter coats, jumpers and wool carpets. But insecticides such as moth bombs can kill off every other insect in the vicinity. Now, some experts – including museums, which can’t expose their artworks to chemicals – are experimenting with a natural ally: tiny parasitic wasps. The wasps are minuscule, barely visible to the naked eye, and lay eggs in moth larvae. Once the moths are gone, the wasps go too. The tiny wardrobe allies have been trialled by the National Trust, and used for pest control on cassava crops. You can order sachets of the wasps online. ‘ Guardian
maybe considering leaving a wasps’ nest if it isn’t a threat to you;
starting composting: Even on the coldest winter days, compost heaps provide warm, safe habitat for insects to thrive. Over time, compost also improves soil structure and fertility, providing food and habitat for other garden insects.
growing a hedge rather than erecting a fence: Hedges are an essential refuge for wildlife, clean our air, capture carbon and reducing flooding. One excellent all -round choice is Common hawthorn, which supports hundreds of insects’ species; it is a food plant for several moth caterpillars and its flowers are eaten by dormice and provide nectar and pollen for pollinating insects. In the autumn its haws are eaten by migrating birds as well as small mammals. Other must have plants to include in your mixed hedge are blackthorn, hazel, pyracantha and holly. Where you have inherited a wall or fence, not all is lost; plants loved by insects which will grow happily are ivy, cotoneaster, clematis, honeysuckle and ceanothus.
making corridors to interlink wilder areas (such as we now have here on the south side of the main Chesham to Cholesbury road where fewer residents now mow outside their properties).
limiting hard surfaces and decking. Paving over our front gardens is bad for wildlife as well as exacerbating the effects of climate change. Nationally over 12% of households have converted their front gardens into driveways. This loss means nature has less space for wild creatures (bees, butterflies, birds and hedgehogs) to shelter and feed from as fewer plants are available to them. Rather than paving use gravel, which has the benefit of reducing flood risks. We now experience downpours rather than steady rain which is flushed off this impermeable surface instead of being slowly absorbed by the soil and grass.’
turning out the lights: ‘Everyone has seen moths circle a bulb at night. But if that light stays on, researchers estimate one-third of insects trapped in its orbit will die before morning. Light pollution is a huge driver of insect declines: it changes insect behaviour and can even make leaves too tough for them to eat. It is also a relatively easy one to solve, says Brett Seymoure, a behavioural ecologist at Washington University in St Louis. “Once you turn off a light, it is gone. You don’t have to go and clean up, like you do with most pollutants. I am not saying we need to get rid of light at night, I think we just need to use it wisely.” You can help by switching off your outdoor lights or putting them on a sensor, and shading windows so they’re not shining out into the night. You can also ask your local council to consider switching off some street lights for at least part of the night, particularly in parks and nature reserves – a move that studies have shown benefits insects and saves councils money.’ Guardian
David also showed us an alarming graph which demonstrated the amount of land which is given over to humans for farming to feed us (70% of UK landmass) and for housing us (94% in total as against 6% for all other creatures). It would help if we were all to eat less meat. He also suggested that we lobby our politicians regarding the use of pesticides and fertilisers; to encourage more farmers to leave a strip of uncultivated land around fields; and to re-instate more hedgerows.
Importantly, we should involve young people in learning about the beauty of the natural world and the importance of insects in the maintenance of this unique planet.
Many thanks to David, John and to journalists such as Tess McClure and Patrick Greenfield in The Guardian for raising this important topic and for showing us that, as individuals, there is a great deal that we can all do!
Lindsay Griffin