Bee Keepers’ Day – The decline of insect pollinators

Yesterday I went to the Federation of Middlesex Beekeepers’ Associations annual ‘Bee Keepers’ Day‘. Each year the Middlesex associations (Ealing, Enfield, Harrow, North London, Pinner & Ruislip) take it in turn to host a day of beekeeping talks; this year the day was held in Ruislip. Below are my notes from the first speaker.

Dr Stuart Roberts of Reading University, Centre for Agri-Environmental Research. The decline of insect pollinators’

Dr Roberts began by asking the question: is there a bee decline or not?

Before trying to answer this, he gave an overview of just how many bee species there are. There is only one species of honey bee native to the UK (the European honey bee, Apis mellifera). There are rather more species of bumbles: 25ish. The reason for the ‘ish’ is that a few species have only been spotted near the Channel and may have been blown across. The honey bees and the bumbles are the bees you are most likely to have seen. Going unnoticed and unappreciated by most people here are a whopping 240 other bee species, such as little solitary and parasitic bees.

Worldwide we have 9 species of honey bee, 25o bumble species and a staggering 19,300 other species of bee in total, many of which in the tropics come in shimmering tones of metallic blue, green or violet. The blog is a good place to see galleries of these jewel like bees, I found the photo below there.

In size, the world’s bees vary from a tiny 2mm long, such as the least carpenter bee, found in southern Europe, to the huge 39mm Wallace’s Giant mason-bee, a species believed to be extinct until 1970s and still threatened as it requires primary forest. This research paper by its 1970s re-discoverer, Adam Messor, has a photo showing just how collossal these bees are compared to Apis mellifera:

Now, back to Dr Roberts’ original question – are bees really threatened? There is, he told us, a clear difference between a well known fact and a widely held belief, even though these two things are often confused. To try and distinguish between the two, Dr Roberts’ and his colleagues at Reading University have spent the last four years gathering data on honey bee numbers. At first he thought it should be relatively easy to put such datasets together, but in reality he found reliable data was scattered and published in obscure, hard to track down journals. There is a need for consistently gathered data across countries. Not all countries require beekeepers to register their hives, and there is a considerable black economy of honeybee products in Europe. Migratory beekeeping in the USA makes it hard to collect data – where and when do you count the bees?

When it comes to honeybees, saying whether we’ve had a decline depends when you start counting! In Europe hive numbers are generally higher than in the 1800’s but lower than since the 1980’s. There has been roughly a 23% decline in colony numbers and a 36% decline in beekeepers in central Europe since 1985. The introduction of varroa may have something to do with this. The Mediterranean basin bucks the trend, with a genuine increase in beekeeping and Mediterranean hillside honey particularly in demand.

Next Dr Roberts turned to bumbles and solitary bees. In one historical source, the shrill carder bee (bombus sylvarum) is described as the ‘commonest bumblebee’. It has sadly greatly declined here, so much so that it is now restricted to only four grassy sites in southern England and Wales. Many species of solitary bees show a great decline too. Specialist species which forage on a particular crop or nest in a particular type of place, such as the ‘snail shell bees’ bee artist Val Littlewood has drawn so beautifully for us, tend to be more in decline. Species which produce more brood cycles during the year (double brooders such as Bombus hypnorum) and generalist feeders are doing better.

The shrill carder bee, so called because the queens fly very quickly, producing a high-pitched buzz

Dr Roberts concluded that the decline of bee species is occurring everywhere, although the larger the scale of the area you look at the harder it is to measure decline. Many reasons for the decline have been put forward – some fanciful..

  • Car exhaust – compared with wholesale destruction of habitat, probably a small impact, Dr Roberts said
  • Mobiles – “cited in some appalling papers”
  • Electromagnetic fields from power lines – “no evidence”
  • Osama bin Laden – “bonkers suggestion but at least is now testable”!
  • Whisked off to heaven in the rapture – no need to comment.

More serious suggestions include:

  • Monocrops
  • Agrichemicals
  • Large-scale migratory beekeeping
  • Plus parasites and pathogenic viruses affecting bees already stressed by the above, e.g. varroa, small hive beetles, tracheal mites

For bees in the UK in particular, Dr Roberts sees the following factors as the biggest problems:

  • Habitat loss – 50% of the problem, so much prime bee habitat has been lost to housing, golf courses, gravel mining, conifer plantations, kebab shops…
  • Intrinsic factors such as low population densities & restricted range – some bees have always been rare
  • Native species dynamics – some favourite species of plants are declining and, in the case of parasitic bees, some host species are in decline
  • Climate change

People tend to think honey bees do the most pollination but in fact for agriculture the contribution of honey bees is only about 8.7%. The combined value of all pollinators to UK agriculture is £402m per annum, of which honey bees only contribute £38m pa. Why bother about saving the other pollinators? Why don’t we just put in more honey bee hives?, Dr Roberts was asked when he went over to Washington DC to speak. In reply to that, he pointed out that you don’t make up a football team using only quarterbacks. It’s not a good idea to try and rely on just one species.

Some plants can’t even be pollinated by honey bees, such as tomatoes and bell peppers, which require buzz pollination. 50,000 bumbles are imported here each year for pollinating these types of crops in poly tunnels. The preferred species are the European type of Bombus terrestris, the buff-railed bumble. The buff-tail is one of the top five bumbles you are most likely to see in a UK garden, but the ones found in poly tunnels look different. The breeders rear for large specimens which have a rapid turnover of colony and produce a small number of workers in relation to sexuals (males & queens), so that farmers have to restock more frequently and spend more money doing so. Allowing these bees to escape from a poly tunnel breaks the law – but how do you control this? There is already suspicion that American species of bumbles reared in Europe and transported over to the US for commercial purposes have escaped and spread European pathogens amongst wild populations.

A  buff-tail I photographed last summer. Those found in poly tunnels have a bigger body but less of a ‘buff’ to their tail.

Is there any good news amongst all these indicators of decline? We should not despair, said Dr Roberts. He believes this is not a catastrophe – yet. We have noticed the problem in time to do something about it and much research is currently going on.

On a personal scale, we can all do something to help bees. How great would it be if everyone who read this post planted a bee-friendly flower somewhere this spring? I have a strip of garden which is something like 3 x 6 feet and mostly in constant shade from fences and walls. Yet last summer, by putting a few bee friendly pot plants in, including lavender, rosemary and mints, I was able to attract bumbles and other pollinating insects to this unpromising spot.

Dr Roberts recommends a book called ‘Befriending bumble bees‘ by Elaine Evans for information on attracting and even rearing bumbles. And don’t forget the little solitary bees – Dr Roberts has put on his garden wall the most extravagant solitary bee nesting house he could put in “without needing planning permission”! It has 1,000 tubes and last summer every single tube was occupied. Not just by bees but by tiny solitary wasps too – which handily hunt garden aphids.

The type of nesting sites which solitary bees enjoy. There is a photo of Dr Robert’s actual super deluxe bee hotel here – it is a thing of beauty:

Also, check out this post by Morgan Bowers on the Invertebrate Challenge Project in Preston: ‘A Luxury Bee & Bee‘  – her group has built the biggest solitary bee hotel I’ve ever seen:

huge solitary bee hotel
Photo by Morgan Bowers, from her ‘A luxury Bee & Bee‘ post.

And a final example, from the ‘Food from the Sky‘ project above Budgens supermarket, north London:

Follow-up posts:

Bee Keepers’ Day 2 – Improve your bees and beekeeping – simply
Bee Keepers’ Day 3 – How the National Bee Unit protects our bees

About Emily Scott

I am a UK beekeeper who has recently moved from London to windswept, wet Cornwall. I first started keeping bees in the Ealing Beekeepers Association’s local apiary in 2008, when I created this blog as a record for myself of my various beekeeping related disasters and - hopefully! - future successes.
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19 Responses to Bee Keepers’ Day – The decline of insect pollinators

  1. disperser says:

    I like the tube idea . . . I will give that a try here.

    The logs look like they just have holes drilled into them, or are those made by the insects (some wasps seem to bore, or at least they looked like they did in my shed in Michigan. Perhaps they were using holes made by other insects.


  2. disperser says:

    Forgot to subscribe to the comments, so posting this one just to subscribe.


  3. I love those jewel bees! They are so beautiful!


    • Emily Heath says:

      I know…would love to see them one day!


      • daveloveless says:

        When I lived in Brazil, I used to watch for the metallic bees. I’ll be honest, I didn’t know they were bees back then, but they were fascinating and beautiful to watch.

        My favorites were these rich metallic blue ones. They looked like silvery turquoise. Fantastic.


        • Emily Heath says:

          They sound amazing. Some of the tropical male solitary bees apparently hunt out chemical scents produced by orchids, which they collect using combs in their legs, in a similar way to honey bee pollen baskets. They then release the scents at mating sites in the forest to attract females. Very romantic stuff.


  4. beatingthebounds says:

    Absolutley fascinating. I like the idea of being a friend to bumble bees – I shall be installing some sort of multi-storey holes home in our garden (we already have healthy supplies of mint, lavender and rosemary) and will let you know when I’ve done it. There – that sounds scarily like a promise.


  5. I too love the jewel bees. I think I photographed one last summer, and now I can look at it compared to your image. I especially like that buff-tail, as I never saw one like that before. Another great and informative article, Emily.


  6. Emily,
    You have really done a great job with your blog; very nicely done.


  7. hencorner says:

    There you go… missed you again! I couldn’t make Saturday 😦
    Really glad to have a solitary bee bamboo house in the kitchen garden to pollinate the tomatoes & peppers!


  8. Pingback: Disappearing bees – countdown to catastrophe or one to watch? | Miss Apis Mellifera

  9. Thanks for an interesting post – there was quite a bit in the press earlier this year about the neonicotinoid insecticides and bees, how much of a problem do you think these really are in the UK??


    • Emily Heath says:

      Thanks Philip. As a city beekeeper it’s hard for me to tell. I hope people locally aren’t using these insecticides – but there’s no way of me knowing if they are or not. I’d be a lot more worried if I lived near oil seed rape fields. The biggest thing I’m worried about is habitat destruction causing loss of nesting sites for native bees, as well as loss of forage. Most of all, bees need homes and food.


  10. Pingback: “Bee foraging on garden plants: Sussex University research” – a talk by Professor Francis Ratnieks | Adventuresinbeeland's Blog

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