Tuesday 5 February 2013

Making 'house signs' so bees can find their own hive

Everyone knows that foraging honey bees can find their way back to their home and that ‘guard’ bees will stop any ‘foreign’ bees from coming into their hive. 

Well, actually, this is not quite true.  In the wild, colonies of bees would set up home with their hives well separated from each other.   However, for the convenience of the beekeeper, we tend to put our beehives within a few feet of each other.  Also, the guard bees are quite practical.  If a worker bee turns up at the doorstep with a full load of nectar, they will generally just let it in ... well, why not!

This all tends to create a bit of a problem for the beekeeper.  If the bees cannot tell the difference between the hives, then they tend to just go to the nearest one!

I have to keep my beehives in a line, because they sit on a concrete path at the edge of a building, with a collapsed cellar in front of them.  This keeps people separated from the bees, but it tends to confuse the returning worker bees.  The bees see a row of almost identical green beehives, so they tend to just go into the nearest one!  For several years I thought that I had one colony that always collected more honey than the other hives, until I noticed that, regardless of the state of the colony in the end hive, they were always the best honey producers!

I tried turning each hive’s entrance in a different direction, but it made little difference, so finally I realised that the bees needed house numbers on their hives!

Unfortunately, bees cannot read, and they see different colours to us, so it is a little more complex than painting a number on each hive.   Beekeepers in lots of other countries paint their hives to help the bees to find their ‘home’, but rather than randomly painting, I thought I would apply a little science.

My apiary with hives with new signs on their roofs

Carl von Frisch (who won a Nobel Prize for his research into bees, including discovering the ‘waggle dance’ that bees use to tell their sisters where to go to find nectar producing flowers), found that bees cannot see red, but can see a colour we cannot see ‘ultra violet’.  (von Frisch, 1950) 

He found that 4 colours can be easily distinguished by bees; white, yellow, blue and black.  Since I wanted to paint ‘signs’ one of these colours has to be the background.  I chose a black background because I found some scrap black plastic to paint on (if you are looking for recycled bits and pieces like this then if you are near enough, I recommend you go to Worcester Resource Exchange (WRE)).

Von Frish also found that bees cannot distinguish between a square and a circle or a triangle.  However they can distinguish between a square and a cross.  He thought that this is because their eyes are evolved to distinguish between different types of flower, so they can tell the difference between a smooth flower, with only a few petals, like a poppy, and one with lots of petals like a daisy (for pedants among you, poppies are not pollinated by bees and daisies are compound flowers, made up of lots of single petal florets!).  So, to make things easier for the bees, I decided to use three patterns for the house numbers; \, X and *

This gave me 9 combinations of colour and shape for their ‘house numbers’, which I then mixed up so that no two colours were next to each other:

1)            Blue \\
2)            Yellow XX
3)            White **
4)            Blue **
5)            White \\
6)            Yellow **
7)            Blue XX
8)            Yellow \\
9)            White XX

Freshly painted beehive roof signs

I painted the pattern on each black plastic plate twice, partly because the plate was big enough and partly to make it look more like a group of flowers for the bees.  As you can see from the photo, I also painted a ‘human readable’ number on each plate so I got them in the right order if I moved them!

Each plate has two loops of elastic going through hole in the end.  These loops go round a house brick.  I have always put a brick on the top of my hives to help prevent the roof blowing off in high winds, so I just looped the elastic round the brick on each hive.

Sign on beehive roof, tied to a brick

I have been using them for three years. The photos are from when I recently took them off the hives for repainting.  Judging by the height of the beehives in the summer, it seems to have worked in equalising the hives, so I think it must have made a difference!  I certainly hope it continues to work, because my daughter took up beekeeping in the last year. Her hive is in the spot at the end of the row of hives. I want her to learn how to manage her bees to make honey, not to just collect extra from the other hives in the apiary!

Works Cited

von Frisch, Karl. 1950. Bees: Their vision, chemical senses, and language. s.l. : Cornell University Press, 1950. ISBN 0-224-02214-8.
WRE. Worcester Resource Exchange. [Online] http://www.wre.uk.com.