Bees and pesticides

A group of pesticides that are harmful to bees and other pollinating insects have been banned by the EU. But why are bees important for wildlife?

The European Commission has placed a temporary suspension on dangerous insecticides called neonicotinoids. The ban will has been in effect from 2013 and restricts the use of the three most common neonicotinoids (Imidacloprid, Clothianidin and Thiamethoxam) on crops which are ‘attractive to bees’.

A report by the European Food Safety Authority (EFSA) identified a ‘high acute risk’ to honeybees from Imidacloprid, Clothianidin and Thiamethoxam, and an unknown risk to other pollinators such as bumblebees and hoverflies. The EFSA is to update the assessment of the risks posed to bees by neonicotinoids by January 2017. 

But why are bees important and what is their value to the wildlife of our three counties?

 Pollination is vital, and one of many reasons why people should care about insects.  

Bees are vital to life:  a high proportion of world crops are pollinated exclusively by bees.  The reason for this is often overlooked:  the whole evolution of colourful flowers, over the last 100 million years, is an unimaginably complex process of co-evolution between flowers and insects, most prominently, the bees. Until insects discovered flowers, plants were all wind-pollinated, in the way that grasses and the trailing catkins of hazel bushes are still today.  But whenever you see a brightly coloured flower, it’s a specifically evolved structure to attract insects, so that they will carry pollen, with far more precision and far less waste, from one flower to another of the same species.  It’s also why different flowers look, erm, different: so that bees can concentrate on one at a time, and not squander pollen by transferring it to the wrong plant. 

Why bees are popular?

I think there are more reasons why  people like bees.  They are furry, and have two large eyes, making some, especially the bumble-bees, the teddy-bears of the insect world.  They are colonial, and are the epitome of hard-working creatures, because they have to gather nectar and pollen to rear the brood. And their buzzing is a soothing, reassuring sound of Spring and Summer.

Local bees and local landscapes

Our three counties are still important for bees.  Many rare or scarce species still occur in our area.  We have some fabulous habitats for bees:  our best heathlands, like Cooper’s Hill and Rammermere Heath in Bedfordshire; our chalk and limestone grasslands like Totternhoe and Blow’s Downs in Beds, Collyweston and Old Sulehay in Northants, and the flower-rich rides through our richest old woodlands, are all great places to see bees thriving.

These are all places where the food supply -  a continuity of rich nectar and pollen sources throughout Spring and Summer  -  remains excellent.  Most of these places have a large expanse of habitats, with scrub and rough grassland, full of mouse burrows and other good nesting sites.  And most have a good habitat structure, with woods or belts of trees which provide shelter (and sunny hollows which are warm enough to forage in even on cold days) and also block or reduce pesticide spray drift from nearby arable land.

We have also created some fantastic new habitats for bees and other insects.  Sammocks Hill at Old Sulehay has a breathtakingly rich limestone flora already. 

How do neonicotinoids affect wild bee populations?

Apart from the honey bee, all our wild bees, including bumble-bees and solitary bees, have an annual life cycle.  Queens come out of hibernation, start a nest, lay their first eggs and feed the brood.  When the first generation of workers hatch out, they start feeding the next generation, and the queen spends more and more of her time egg-laying.  By around the middle of summer, bumble-bee nests  begin to produce males and new queens.  These mate, feed for a few weeks, and those new, mated queens are the only ones which survive to hibernate, and then repeat the cycle.

So, the survival of the species is reliant on enough nests producing enough queens and males at the critical time.  This depends on the foraging efficiency of the workers.  There is good evidence that neonicotinoids, which are nerve poisons with an irreversible, cumulative effect, can impair the foraging abilities of worker bees, essentially confusing them.  So, although the bees are not themselves killed, they may collect less food, so the young in the nest grow more slowly. 

Each year, more scientific research is published which confirms the effects of neonics and widens the scope of the damage they cause. The latest findings show that there is a substantial impact on wild bee populations, many of which are also essential pollinators of crops, but which are equally vital as links in the natural environment. Most of our nature reserves are surrounded by arable crops and we cannot prevent ‘our’ bees foraging on farmland, where they would be seriously at risk if the rape seed had been treated with neonics.

In a perfect bee-friendly landscape, neonicotinoids might not matter very much.  Imagine an area which is very rich in nectar-rich flowers, where the habitats are well connected, with sheltered flight lines, so foraging bees can safely travel through the land, and find ample food close to their nests. Imgine a warm summer with perfect foraging weather, but enough rain to keep plants growing.  In these conditions, the bees might be able to cope with a small reduction in their efficiency.  Unfortunately, for the last 70 years, the abundance of wild flowers in our landscape has been declining. 

With a meagre food supply, a fragmented landscape, and often with bad weather, bees can barely cope in the modern English countryside.  Making them less efficient at foraging with minute doses of neonicotinoids may well be the last straw. 

We cannot take the risk. 

You can help too!

If you have a garden, a window-box or a couple of pots on a patio, at home or at work, you can help bees.  Grow flowers which produce abundant nectar, and are shaped so bees can feed from them.  Most herbs, such as lavender, thyme, marjoram and mints are good. Old-fashioned flowers, with their natural flower shapes, are better than modern scentless, double forms. And if you plant your garden to provide some colour from early spring to late autumn, you’ll be especially popular with bees and other flower-visiting insects:  adding a small sallow or willow, and allowing a patch of ivy to flower, can extend your nectar-season by a month at either end.

Wildlife Trust national position statement on bees and neonicotinoids