Animal migration tracking: how did we get to bee backpacks?

Bees are in trouble. We know this, but we don’t know why. It’s a serious problem: one way or another, around one-third of the world’s food production is dependent on the yellow-and-black-striped buzzers. While those who say humans would follow if bees were wiped out are scaremongering to a degree, nobody denies that bee extinction would certainly cause severe problems.

Bee pollination is responsible, directly or indirectly, for a variety of foods including apples, onions, carrots, cucumbers, cauliflower, celery and broccoli. Supermarket chain Whole Foods illustrated the problem by showing what their stock would look like with and without honey bees:

“Big deal,” you may be thinking, “I don’t even eat celery.” Me neither, but myriad plants would also struggle without bees, and this would probably kick up the foodchain to affect something you do eat.

For such a small insect, the bee certainly punches above its weight – in fact, every year bees contribute around £150 million more to the economy than the Royal Family (although it’s hardly a fair comparison, given the relative frequency of queens in the hive).

But I digress. We know bees are vanishing –around one-third of the US’s commercial bee colonies vanished in 2012 alone – but we don’t know exactly why. While a number of interesting theoretical solutions to the problem have been mooted, we’re really just chucking a load of ideas at the wall and hoping something sticks.

So, how do we find out more? Well, Tiny bee backpacks will help.

Excuse me?

Sorry, quite right. Tiny bee backpacks might help. These microsensors have been glued to the backs of 10,000 honey bees to try to figure out the causes of colony collapse. The battery in each is powered by the vibration of the bee, meaning it will keep transmitting until the bee dies.

Receivers placed around bee hives track data from each sensor, including how far they travel and how long they’re gone, but also how each bee interacts with factors that have been blamed for the fall of bees: exposure to pesticides; air pollution; water contamination; weather; and diet.

Each 2.5mm x 2.5mm pack weighs 5.4 milligrams, which sounds like nothing, but it’s the equivalent of you or me having two 13in Macbook Pros strapped to our backs. And we don’t even have to fly anywhere.

“The bees fitted with sensors aren’t able to carry as much pollen, but we do learn a lot about the bees by doing this,” Professor Paulo de Souza, science leader at the Commonwealth Scientific and Industrial Research Organisation, told the BBC. With that in mind, a new generation measuring 1.5mm x 1.5mm is being designed to interfere less with insect behaviour.  

History of wildlife tracking

While it has seldom been done on this scale (putting a GPS sensor on a bee would mean it couldn’t take off), scientists have been tracking wildlife one way or another since 1803. Ornithologist John James Audubon pioneered bird banding by tying strings to the legs of Eastern Phoebes, observing their pattern or returning to the same nest every year. Ornithologist John James Audubon

Bird banding became more sophisticated by the end of the century, with unique ID codes created for each bird.

In 1933, a paper written by Frank Blanchard and Ethel Finster championed “scale clipping” – a system for identifying individual snakes by scarring patterns created with microsurgical scissors. A far from perfect solution, for scientists and snakes.

The impact of war

The second world war introduced radar (a technology that had been in development for 40 years) as a possible solution for wildlife tracking – although not intentionally. Migrating birds created “radar angels” on screens that were supposed to be tracking enemy movements.A 1950s fixed-site acoustic receiver system

Another unintended development from wartime was acoustic telemetry, which has its origins in sonar; it was developed to hunt submarines during the first world war. In 1956, the American Bureau of Commercial Fisheries and the Minneapolis-Honeywell Regulator Corporation created the first equipment to track fish migration in this way. This was perfect for tracking sealife, since sound waves travel far better through salt water than radio waves, which tend to be absorbed.

The 1960s saw the introduction of VHF (Very High Frequency) telemetry, which involved physically collaring an animal with a VHF transmitter. Three or more directional antennae could then triangulate the position of the device, revealing the location of the creature being tracked.

Modern times: shrinking sophistication

A PIT tag next to an American penny

PIT (Passive Integrated Transponder) tags were the next significant development, and marked a big leap for wildlife tracking technology in the 1980s.

Each tag – about the size of a grain of rice – contains a chip, a capacitor and an antenna in a glass case. Tags don’t require their own power source and lie dormant until scanned with a low-frequency radio signal; this creates a close-range electromagnetic field, which in turn sends the unique alphanumeric code back to the reader.

Crucially, detection doesn’t require the animal to be captured twice: the passing of a reading antenna will do the job.

The 1990s brought GPS technology into mainstream use, although initial models were too large for animal application. By the middle of the decade, though, the technology had been refined and shrunk enough to allow animal movements to be accurately tracked using signals sent to satellites orbiting Earth.

For tracking big cats, this can prove expensive. Popular Mechanics reported that the collar used to track Cecil the Lion before his death cost $2,340, plus a $780 annual charge for downloading the data. ‘Can you pick up the football scores with that thing?’

The 1990s also saw the advent of genetic markers – DNA sequences that identify species’ and individuals. The problem with this, of course, is that animals need to be captured twice in order to do the necessary tests.

With the rise of nanotechnology in the 2000s, scientists have been able to track even smaller creatures. The technology is there to go even as small as single proteins using quantum dots. The long-term exploration of this research will likely lead to far greater medical understanding than we have now.

Indeed, the best may be yet to come, as researchers from the Smithsonian Tropical Research Institute said this year: “We suggest that a golden age of animal-tracking science has begun. The upcoming years will be a time of unprecedented, exciting discoveries.”

In short, the bee technology is amazing – but the journey that science has taken to get there in the past 200 years is just as brilliant. We’ve come a long way from tying bits of string to animal legs – a fact I’m sure CSIRO’s experimental bees are extremely happy about as they strap on their 5-milligram backpacks.

Images: Csiro, Hugh McGregor and public domain