Some thoughts on climate change and bees

honeybee on yarrow

There can be no overstating the importance of bees both domesticated and wild, for the purpose of pollinating food crops. They are indeed some of Nature’s miracle workers’.
(It takes a combined average of about 55,000 ‘Bee miles’ to produce 1 lb of honey!)
Bees however are being impacted by neonicotinoids and other man-made chemicals that are a believed cause of ‘Colony Collapse” the world over.
Another often overlooked cause of the decline of pollinators, specifically bees, is climate change.
In order to make this connection, we should first examine a bit about how and when bees leave the hive and fly.
You may have heard this statement or something like it in the past;
“According to all known laws of aviation, there is no way that a bee should be able to fly. Its wings are too small to get its fat little body off the ground. The bee, of course, flies anyway. Because bees don’t care what humans think is impossible.”
This is however something of a myth. We do know that early on and for nearly 80 years biologists believed that a bee’s wings were very rigid similar to that of an airplane’s wings. The argument was that if this is so, then the size of the bee’s wings, in proportion to its body, makes it impossible for it to gain the necessary lift to fly.
It turns out that bees have two sets of wings. A larger outer set and a smaller inner set that are connected to each other by small comb-like teeth, producing a larger surface that helps bees create better lift and fly.
Similar to the way the muscles of our lungs expand and contract for us to breathe, bees have a muscle that causes the thorax to alternately contract very rapidly thus causing the wings to beat (as much as 230 beats per second) and it is this that creates the buzzing sound that bees make!
A typical honeybee can fly an average of 15 miles per hour, (only about 12 mph when laden with pollen or nectar or when wet) with a maximum known speed of 20 mph.
By comparison, a Bumblebee flies at around 7 mph but has a max of 33 mph!
Yellowjackets and Hornets are clocked at 7 mph and 14 mph with maximums of 30mph and 14 mph respectively.
Okay, all well and good so far.
In order for a forager bee to even leave the hive there are several important climatic conditions that must be met;

1 Dry weather. Bees can fly in the rain if it’s a light rain but they prefer not to.

2 Wind speed. The maximum wind speed that a bee can fly in is about the same as it can fly. When the wind is 20 mph or more they will not leave the hive. If they are caught in wind while out from the hive (up to two miles in any direction) they will find a stable perch and hunker down to wait it out. At wind speeds of about 5-10 mph, bees will begin flying lower to the ground to conserve energy. Higher wind speeds also reduce the number of flowers a bee will visit per minute by about half.

#3 Temperature. The minimum temp that a forager bee will leave the hive is 13C -55F. And in order for the majority of the hive to activate the temperature needs to be 19C or about 66F. The main reasons for both the wind and temperature restrictions is that they cool the bees and cause them to struggle to such a point that their energy return makes it inefficient to fly.


Curiously bees are not only extremely energy efficient but also highly sensitive to weather and can foresee changes in the weather well in advance.
As we go deeper into the current climate crisis many areas have experienced increased wind and rain while others have had cooler, chillier summers.
Since we can’t really control these factors what can we do?
Along with confronting the climate crisis globally on all levels; ecologically (protections and scientific investments), sociologically (education), politically (leadership change and legislation) and economically (real ‘Green profits’), there are also a few small things we can do now;
It is important for beekeepers to locate their hives in sheltered areas with good forage close at hand.
The thing that the home gardener can do, apart from not using pesticides, is to provide pollen and nectar-producing plants for our Bumble and other wild bee populations. Although Bumblebees do not produce honey, they are exceptional pollinators.
Additionally, those plants that have umbel-shaped flowers (Yarrow, Fennel, Wild Buckwheat, etc) make terrific landing pads for many beneficial insects.

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