Tiny dancers: Scientists spy on booty-shaking bees to help conservation

WASHINGTON (AFP) – We have long known honey bees shake their behinds to communicate the location of high-value flower patches to one another, a form of signalling that scientists refer to as “waggle dances”.

A group of United States (US) biologists have now decoded the meaning of over 1,500 of these jigs, providing conservation groups trying to boost the imperiled species’ population with new insights into their dietary preferences.

“The thing I think is the most interesting about bees is their communication,” PhD student at the University of Minnesota and the lead author of a new study published in the journal PLOS One Morgan Carr-Markell told AFP.

“So I wanted to be able to use that to help land managers who are interested in planting for bees, and give them on-the-ground information.”

Carr-Markell and colleagues set out to answer two main questions: What types of flowers do these foragers seek out for pollen and nectar, their two main sources of food, and when do they engage in most of their foraging activity?

Honey bees in their hive at an outdoor Farmer’s Market, in Washington, DC. PHOTO: AFP

To find out, the researchers placed bee colonies in glass-walled observation hives at two sites – the Belwin Conservancy and Carleton College’s Cowling Arboretum in Minnesota.

Before European colonisation, the midwestern state was covered in prairie lands, but today less than two per cent of the original grasslands remain.

This is one of several reasons behind a precipitous decline in bee populations that has raised alarm because of the essential pollination services they provide.

Many conservation groups are actively involved in trying to revive these habitats, but there are major gaps in our understanding about the bees’ foraging strategies and how best to help them.

Between 2015-2017, the team recorded waggle dances of female bees in these hives on their “dance floor”, just inside the hive entrance (the male bees are known as drones and their sole purpose is to mate with the queen).

It involves repeated figure-of-eight runs. During the straight part of the figure-eight, the dancer waggles back and forth to define the direction of a flower patch relative to the sun on the horizon, by making an angle with her body.

By decoding and mapping the flowers that the bees signalled, Carr-Markell learned that “honey bees were more likely to communicate with their sisters about nectar sources in prairies in the later part of the foraging season”, in the months of August and September.

But the team was not only interested in when the bees were more likely to visit prairies – they also wanted to know which particular flowers excited them.

“We can actually say for sure that seven different native prairie groups were advertised by our bees as really good pollen sources” including goldenrods and prairie clovers, said Carr-Markell.

The research comes at a tough time bees, vital for growing the world’s food as they help fertilise three out of four crops around the globe, by transferring pollen from male to female flowers.