Focus on: Insect Decline and the Great Yellow Bumble bee

The great yellow bumblebee on red clover © Jamie Boyle 

DWT’s President, Dr George McGavin, is an entomologist, author, academic & television presenter who is passionate about insects. In this article (which can also be found in the DWT summer magazine), George explains why we should be worried about the disappearance of insects, and why we need to act fast to reverse their decline, for the benefit of both people and wildlife.

Ask anyone over the age of sixty what the countryside was like when they were children and you may well hear tales of clouds of butterflies and the air ringing with the buzzing of bees and the songs of grasshoppers. If you are a child yourself, you will not recognise this as being an accurate description of the countryside you know today. You might think that they are exaggerating, but I can assure you they are not.  The countryside we see today is very different from that of our parents and grandparents. The relentless demand for land and the increased use of pesticides to produce cheap, blemish-free food has eaten into our natural capital to such an extent that now, many species that were once common, are rare or no longer seen. The reason nobody noticed the change until fairly recently is due to a phenomenon known as the shifting baseline syndrome. If we were to lose half our species in one year it would be blindingly obvious that something disastrous had happened but, year by year, little by little, a small decrease is almost imperceptible  - the baseline is set a little lower every Spring until eventually it dawns on us that things are not quite right. 

Many studies in the UK and elsewhere that have shown the declines are occurring in just about every group of animals you care to mention and recently the issue has gained some coverage in the media. Some of the headlines have been a bit over the top - one claiming that insects would disappear from the face of the Earth in a 100 years. They may become less abundant, but they will not disappear. Insects were among the first species to colonise the land around 400 million years ago and were the first animals to take to the air. They are the most abundant and diverse group of species ever to have evolved and, due to their small size and high reproductive rates, are future-proofed like no other animal group. Nevertheless there are many entomologists and ecologists, myself included, who think there is good evidence that insects are declining, and since insects underpin most terrestrial food networks, the ecological consequences of this may be serious and would threaten the stability of ecosystems. Insects are the world’s major group of herbivorous animals - all the heaving, snorting herds of grazing ungulates are entirely ‘out-munched’ perhaps by a factor of ten to one, by the myriads of tiny mandibles. Insects also consume many times more animal flesh than all the vertebrate carnivores put together.  If this sounds implausible, consider that although insects are individually small, there are an awful lot of them, with an impressively large biomass. Insects are also the food source for countless species of animals. Many trillions of insects a year are eaten by birds, bats and a whole bestiary of other creatures and when they die, it is the insects who recycle their remains.

But there is one vital ecological job role that insects perform, without which life on Earth would be very different. Pollination is perhaps one of the most essential symbioses ever to have evolved. The plants of the Jurassic landscape would have been largely green and brown and it was only the rise of the flowering plants and the insects that were tricked into being sexual go-betweens, that the world became a colourful place. This plant-insect version of ‘I’ll scratch your back if you scratch mine’ has been around for 100 million years and it has given the world a rich diversity of species. Twenty-thousand species of bee are mainly responsible for the continued survival of the 370,000 known species of flowering plants. The loss of pollinators would certainly have an adverse effect on agriculture, since many crops depend on bees and other insects to set seed. From almonds, apples and avocado, cucumbers, cherries and cocoa to pumpkins, plums and peas - our food supply would be diminished and our food security seriously undermined. There are already some parts of the world where there are no bees left and the fruit trees there now have to be pollinated by hand. It would be unthinkable if this was to become the norm.

Queen of the Machair

I have been lucky enough in my job as television presenter, to travel all over the UK to film some of our rarest and most interesting insect species. For one short film I made for The One Show, I travelled to North Uist in the Outer Hebrides to see the Great Yellow Bumble bee, Bombus distinguendus (pictured above). This large and beautiful bee was once widespread across Britain but as the flower-rich meadows on which it depended shrank, it became scarer and scarcer. It is now confined to the extreme north of Scotland and the Western Isles where the unique machair provides it with a suitable habitat.

Get Dorset Buzzing

Happily, it is not difficult to encourage bees and other pollinating insects. 

They simply need the right sort of habitat and the right sources of food and they will bounce back. By avoiding the use of insecticides and providing places for them to nest and suitable plants for them to visit throughout the year we can ensure their survival and ours.  

Click here to find out how you can do more to Get Dorset Buzzing. 

Click here to sign up to the Get Dorset Buzzing campaign by the end of October. 

George and RSPB Uists Warden Heather Beaton with the great yellow bumblebee© Guthrie O’Brien

George and RSPB Uists Warden Heather Beaton with the great yellow bumblebee© Guthrie O’Brien 

Protect Dorset's Pollinators

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Female tawny mining bee © Nick Upton 2020VISION