Visual Aid

I've got to do a presentation to a group of potential beekeepers.

I want to be able to do a slide giving some sort of visual indication of the 'density' of foraging bees on a symbolic map.

[One of them told me recently he was concerned about the school 100 yards away.]

You know, if 20,000 bees* are out foraging on a summer's day, flying for 90 minutes*, with a reach of 3 miles maximum, what sort of density might be expected at 25 yards, 100, 440, 880, 1 mile etc at any one time?

I realise that all sorts of things affect real life, such as topography, vegetation, where the nectar flows are etc. but I think it will be an interesting slide.
Probably quite easy to prepare for someone with a mathematical or IT background.

And if anyone has any other suggestions, I'd be glad to hear them.

Thank.

Dusty

* Figures I've just plucked out of the air.

C'mon Dusty, its bees, it ain't quite like that.

Bee density in the landscape depends on the forage available.
100 yards away, they might not see a single bee all day - but if you put some honey (not that you would, of course) out in a dish over there and you'll have hundreds of them within the hour.
One of the aspects of 'forage' is water, and bees find and use some extraordinary sources - from hot tubs to septic tanks.

The criteria for a safe apiary don't have much to do with what is 100 yards away, but a lot to do with what is within 10 yards or so. High hedges (or fences, even trellis) are a very good thing.



Bees will rarely go as far as 3 miles, but (absent any other food sources, desert perhaps) experiments have seen bees going as far as 10km to a feeding station.
Bees cruising airspeed is about 20mph, so 3 miles would take just 3/20ths of an hour to cover - times 60 for minutes - ie 9 minutes, not 90!
But it ain't as simple as that - its bees!
Foragers (both pollen and nectar) average 10 to 15 trips/day.
But nectar foragers can make up to 150 …
The time per load for pollen collectors is typically about 10 minutes (but 187 minutes has been recorded) as opposed to 30 to 80 minutes (but up to 150 minutes) for a nectar trip. (As quoted by Winston, see below)

Dr Margaret Couvillon of LASI has been doing a lot of work on where bees go on their trips. Earlier work by Seeley is diagrammed on page 179 of Winston's "Biology of the Honey Bee" - scatter plots for recorded waggle dances on 4 consecutive days. On one day all were within 1km, that is except for the one that went 4km … Bees, eh?

Hi Dusty,

You are delving into the realms of probability diagrams and their related spreadsheets ... I've just constructed a spreadsheet on the basis:

20,000 foraging bees (it's reasonable to assume that not all the bees would be out at the same time but lets assume that 20,000 are actually flying for a 'moment in time' analysis. The reality is that there will only be a maximum of 20,000 flying when the conditions and time of day are optimum for foraging).

Flying times 5,10,15,20,25,30 minutes .. this includes foraging times.

I've assumed bees average 15 mph (20mph out 10mph back fully laden). This equates to 440yds per minute.

If you take the area of a series of concentric circles with radii escalating from 10yds to 2000yds and calculate the area of these circles then you can determine the theoretical density of the bees in the various areas. Clearly, because of the concentration of forage and the fact that bees will gravitate to areas of quality forage then perhaps it would be prudent to assume that they concentrate into, for the sake of numeric argument, four segments of 15 degrees.

Clearly the longer the flying time the less frequently a bee will be in a particular location and the only constant will be the number of times they pass the datum point -ie: when they return to the hive.

If you factor all these variables into a constant then you can create a notional two dimensional matrix that tells you ... absolutely NOTHING except ... if there was any constancy in the bees you would not be able to breathe for the quantity of bees in the immediate vicinity of the hive and you would be hard pushed to spot a single bee from the hive once you got beyond about 70 yards !

If you have Microsoft Excel on your computer I will gladly email you the spreadsheet .. but itma is right .... the bees don't conform ! It's worthless ....

You could try Brighton uni, they have a bee research dept. someone came from the uni and did a talk for my association on where do the bees go to forage and they had lots of slides on this kind of thing.

A 2D map is of course irrelevant. Bees fly. Try a 3D one.

That will keep you busy until 2015..

Mrs Webmuppet said:

You could try Brighton uni, they have a bee research dept. someone came from the uni and did a talk for my association on where do the bees go to forage and they had lots of slides on this kind of thing.

Click to expand...

Dr Margaret Couvillon is at LASI, part of the University of Sussex (at Brighton) - Brighton Uni is a different establishment!

Maybe you could just get them to watch 'Hive Alive"

madasafish said:

A 2D map is of course irrelevant. Bees fly. Try a 3D one.

That will keep you busy until 2015..

Click to expand...

Or in my case ... probably the rest of my life !!

Spacial graphics come to mind with a hive in the middle with bees exploding out in all directions and touch screen technology so you could touch a section of the 3D 'fly out' which would give you an instant count of how many bees were in that particular section at that moment in time ... masochists - name on a postcard to Dusty please !

26?

pargyle said:

Or in my case ... probably the rest of my life !!

Spacial graphics come to mind with a hive in the middle with bees exploding out in all directions and touch screen technology so you could touch a section of the 3D 'fly out' which would give you an instant count of how many bees were in that particular section at that moment in time ... masochists - name on a postcard to Dusty please !

Click to expand...

We do this kind of research, we use a 3D tracking system, so you can interact with the 3D Image or Model (in 3D) - we call it Visualisation.

and it's done at HIVE (Hull Immersive Visualization Environment) - http://www2.hull.ac.uk/science/hive.aspx

A simple bit of maths comes up with a bee every 31mm on the circumference. Totally unrealistic, but a starting point.

That would be if all 20 000 flew out together, at the same speed, equally in all directions at the same height above the ground, for a flat area and no wind!.

Not really ever going to happen is it? Probably at 3m altitude anyway. Unless there was forage at the location.

Foraging bees are a low level hazard as they would only sting if trapped; the problems only arise with defensive and following bees, which is entirely a different matter. Not very many defenders/attackers, but a huge risk within whatever range they defend.

Hence the need for some on here to petrol their colonies or to be kicked off their allotment site, etc etc.

itma said:

…
Dr Margaret Couvillon of LASI has been doing a lot of work on where bees go on their trips. …

Click to expand...

And, prompted by a mention in Beecraft, I discover that her work has been published http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093495

and this graphic is what I had in mind for you
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093495.g004/powerpoint
During her talk, she showed a time-lapse movie of these probability distributions, where you can see the gradual and sudden changes in 'flows'.

Colour denotes how many dances fall within 25×25 m bins. Black circles are 3 and 5 km from the hive locations (centre black dot). White circles indicate the areas corresponding to the 90th and 50th foraging distance percentiles. Foraging range, containing a diversity of urban and rural land-types, extends the furthest (A, D) during summer (August 2009, n = 439×1000 dances; July 2010, n = 340×1000 dances), less far (B, E) in autumn (October 2009, n = 401×1000 dances; October 2010, n = 231×1000 dances), and least far (C, F) in early spring (March 2010, n = 114×1000 dances; March 2011, n = 195×1000 dances) when flowers are readily available.

Click to expand...

I note that in midsummer the bees are foraging in Brighton, rather than in the countryside …

Thank you, itma.

This is exactly what I need!

And the paper is really informative.

Best wishes,

Dusty