Bees provide us with an invaluable service by pollinating plants, an indispensable part of natural and agricultural ecosystems. This is why declining bee populations are such a big concern. Of course, bees don’t do this as a favour to us – pollination is a side effect of bees collecting nectar and pollen for their nests. But in order to understand bees better, we need to understand more about how they go about finding flowers and deciding how to make the most of them. And this is why I have spent my summers tracking female bumblebees.
Alongside colleagues at Queen Mary University of London and at Rothamsted Research, we published our results in PLOS One, following for the first time every flight of forager bees over the course of their lives. This has given us remarkable insight into the very different strategies taken by different bees in their approach to carrying out their tasks.
From the first time they saw the light of day, emerging from their cells in the comb and knowing nothing of the world around them, we followed four bees as they learned and became seasoned foragers, until their deaths.
Because bees are so tiny, GPS trackers or radio collars are far too large and heavy for them. Instead we used harmonic radar to track the bees, which is excellent at tracking moving objects through cluttered environments full of flowers, hedges, trees, buildings, and other bees. This involves attaching a small, very light electronic transponder to the bee’s back which transforms and reflects the signal in such a way that we can identify the bee. The radar scans the landscape once every three seconds, each time reporting the bee’s position. We used large earth bumblebees (Bombus terrestris) which were bred in captivity, so we knew they were ignorant of the world at the beginning of the experiment. And then we watched their lives unfold over several weeks until, one by one, each left the nest and never returned home.