Bearing up

One of the things that we read about early on in our project was the fact that bumble bees will memorise their nest the first time they leave it by doing "navigation circles" around it. These are a series of circles of increasing size and distance, where the bee looks at the nest and observes the landmarks around it.

On a few occasions we had queens that we attempted to nest and when they left the nest we thought maybe they had shown this "navigation" behaviour. However, there is nothing like seeing the real thing for sure to know what you are looking at. 

I found a great piece of video on the DVR this morning that showed one of our bees in close up coming out of the nest for the first time and spending about 20 seconds up close memorising the entrance. After this, she would have circled at a further distance and height to take in the surroundings properly. (Of course, now she would have the benefit of our "runway" :-) )

So, I already had some iPhone footage attempting to show this circling from a longer distance. So, I've edited the two clips together so you can see what the entire behaviour looks like. It's unmistakable and the behaviour we had seen with earlier queens really did not come close - none of them really memorised the nest entrance like these workers do, even though they circled up to half a dozen times around the nest area. 

My own theory is that the circling we saw with the queens was more to do with them getting their own bearings - bearing in mind (no pun intended) that we'd transported them from the nest site they were hunting down, into our own nest box. Quite possibly a confusing process for them. It makes sense they would have to get a handle on their location once exiting our nest box.

Anyway, here's the video...


Although in the close-up segment our worker is out of shot for some of the duration, you can still see her shadow cast on the nestbox itself. She also moves very quickly so appears to dart about rather than move smoothly.