Where have all the bees gone?

We’re familiar now with the story that bumblebees and other bees have declined over the last few decades. But over recent weeks we’ve had a large number of calls and emails about a distinct lack of bees in places where they’re normally abundant; in many gardens and parks, the bees just don’t seem to be buzzing. Since late June, the number of bees in gardens seems to have dropped dramatically. At first I assumed this was a localised phenomenon, but with a growing number of enquiries coming in, I thought it was best to check with our Data Monitoring Officer, Richard Comont, the man who manages BBCT’s surveys. It turns out he had noticed and had heard the same thing!

So where have all the bees gone? Fortunately, Richard doesn’t believe that anything untoward has happened. In the UK, we’ve had a fairly good summer. Temperatures in Scotland have been higher than average for every month of the summer, and overall the picture has been a good one. But if you cast your mind back to spring, you might remember how warm it was. Using the data from our BeeWalk surveys, we can see that queens of some species emerged over one month earlier this year, compared to last year (bear in mind that last year was one of the coldest and latest springs on record though!). So the warm spring and good summer has meant that many nests will have matured earlier than in previous years. And when bumblebee nests mature and produce new queens or males, they die shortly afterwards. We are used to seeing this for species such as the Early bumblebee (Bombus pratorum) and Tree bumblebee (Bombus hypnorum), but it appears that many more species have peaked early this year, and have since died.

But this doesn’t mean that we won’t be seeing any more bumblebees this summer. While new bumblebee queens usually go into hibernation after mating, we reckon that more queens are starting up new nests instead of hibernating. This could be a risky strategy though, as they’ll need to have a long enough summer to be able to produce new queens of their own before summer ends. So it’s now a race against time to gather food, grow the nest and produce as many new queens (the grand daughters of this spring’s queens) as possible! And of course, other nests will still be growing and won’t have reached their peaks yet, so we expect that the numbers of bees in the gardens should begin to pick up again soon.

We wouldn’t have been able to gather any of this extremely useful data without the efforts of our BeeWalkers, who count the numbers of bees they see on a fixed walk once a month from March until October every year. This is the only scheme collecting data on bees like this, and can allow us to find trends in bumblebee populations. If you’d like to get involved, visit here.

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