Bumblebees with backpacks

By Candice Marshall 13 October 2022
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Right now in Tasmania’s south a group of queen bumblebees are sporting the very latest in insect fashion.

It looks like they’re wearing mini backpacks, but they are in fact carrying around new – and extremely sophisticated – technology.

“These are a new generation of lightweight radio transmitters,” says Dr James Makinson.

James is a postdoctoral researcher at Western Sydney University’s Hawkesbury Institute for the Environment. He is the person attaching these transmitters to Tasmania’s bumblebees. 

Not only are these transmitters small enough to attach to bees, but their batteries last for five days, compared to previous models with only a 12-hour battery life. 

“Similar transmitters have been used in the past on insects overseas, in Europe in particular, but it’s the first time in Australia,” James says.

How are they attached?

“I custom-made a little saddle with a 3D printer that I glue onto the thorax first, and then I clip the transmitter into the saddle,” explains James. 

But first, the bees need to be caught. 

“Bumblebees are quite single-minded when they’re foraging, so when they’re really focussed in on a flower you can sneak up behind them.” 

James then uses a fountain tube to capture them. 

Back at base, the bees are placed in a freezer for 15 minutes, which James explains “cools them down and makes them immobile.”

After the transmitters are attached, the bees ‘defrost’ and are released back into the wild, complete with radio trackers. 

While this process may sound like it would harm the bees, this ‘freezing and defrosting’ is something natural for bumblebees, a regular occurrence for the insects in their cold native European habitats.

What’s the point?

The bumblebee (Bombus terrestris), also known as the buff-tailed bumblebee or large earth bumblebee, was introduced to Tasmania by accident in 1992, via a ship from New Zealand. 

Since then, populations have exploded across the state and the species is now classified as a pest. However, where they nest and what resources they rely on are not well understood. 

James is particularly interested in finding out what the bees get up to during a very specific period of their life cycle. 

“When the newly-emerged spring queen bees are fueling themselves for the upcoming season and collecting resources for their young colonies – this is a critical stage in the life history of a bumblebee colony,” James says. 

“We want to understand what plants and landscapes are important for these bees, whether they’re using native or introduced plants… how they are using the landscape to sustain themselves. We also want to understand where they are choosing to build their new colonies.”

The data gathered using these tracking devices will fill in some very important knowledge gaps and play an important role in the future management of the state’s bumblebee populations. 

“The information that we are collecting could be used in future eradication programs,” says James.

“If an extermination program is planned in the future, we’ll know, at this time of year when the colonies aren’t established yet, when it’s just the queens in the landscape, we’ll know where we can expect to find them,” he explains.

But there’s a flipside. A better understanding of the bee’s behaviours could also be used to promote populations. 

In the Tasmanian agriculture sector, there is strong interest in pursuing the possibility of using bumblebees for crop pollination, much like introduced european honey bees are used on the mainland. 

“They do have a positive impact on crop yields for certain crops,” James says.

“If the government’s policy on these bees was to change at a later date then the information we’re collecting now would also be beneficial in promoting populations in the future.”

In this scenario, the planting of certain flora (found to be highly-frequented by bumblebees) near crops and orchards would attract colonies to these agricultural areas. 

“I’m definitely not trying to support their use in agriculture in Tasmania. This is an invasive species, James clarifies.

“But information is power. So it could be used either way.”

This project is funded by Universities Australia and the German Academic Exchange Service. It is a collaboration between Dr James Makinson from Hawkesbury Institute for the Environment at Western Sydney University, and Dr Myles Menz from the Townsville campus of James Cook University, formally from the Max Planck Institute of Animal Behaviour. James is being assisted in the field by Dr Jon Finch from University of Tasmania, and Ms Anushika De Silva, who has just submitted her PhD thesis at Griffith University.

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