Training Bees to find Buried Landmines

From Bee Craft: October 2009

Sandia National Laboratories, US Department of Energy, and University of Montana, USA

Investigations are in progress to see if foraging bees can help find landmines


Researchers are determining if foraging bees can detect buried landmines. In the foreground are two deactivated anti-tank mines

Sandia’chemists and entomologists at the University of Montana are working together to investigate whether foraging bees can reliably and inexpensively detect buried mines and safely return hundreds of thousands of acres of uncharted land back to productive use.

Landmines have been called the worst form of pollution on earth. Some 60 people are maimed or killed by buried mines every day. The Red Cross estimates that there are currently 80-120 million landmines deployed in 70 countries worldwide, with an average 40,000 new landmines positioned each week.

In many developing countries, thousands of acres of land lie unused because farmers are afraid to work their fields. Streams and other sources of water are littered with mines. In some countries professional mine prodders are paid a few dollars a day to poke the soil carefully every few inches with a metal probe checking for buried mines.


Sandia is working with Jerry Bromenshenk at the University of Montana to see if bees can be trained to find residues of TNT, the primary ingredient of most landmines, and bring the evidence home. The project builds on three decades of explosives-detection work at Sandia and 25 years of biosystems research at the University of Montana.

Bromenshenk and his colleagues have shown that as bees forage they attract particles of dust, soil and pollen to their hairy, statically charged bodies and bring samples back to the hive. In doing so they provide a chemical survey of an area extending a mile or more from the hive in all directions.

All landmines leak small amounts of explosives into nearby soil or water. Sandia’s mine-detection research has focused on predicting what happens in the environment to mine-leaked vapours and residues and their chemical by-products as they are adsorbed on soil particles, permeated or leached through soil, dissolved in water and consumed by animals and plants.


Honey bees forage at a sugar-water feeder with added explosives simulants as part of bee-training experiments at Sandia ries

By modelling the ‘fate and transport’ of explosives and understanding where they concentrate in the environment, the researchers are better able to detect their presence at lower levels and determine optimum conditions for detection.

Based on this work, Sandia is developing a number of mine-detection systems, including handheld chemical ‘sniffers’, soil-penetrating vapour extractors and methods to enhance the chemical signature of landmines. Many of these systems can detect plastic landmines, which most conventional metal detector-based systems cannot.


The bee demonstration in Albuquerque makes use of a remote test area laden with mock mines, specifically built for Sandia’s landmine-detection research. Last autumn, the Sandia team established two small honey bee hives in the landmine field. They also established two control colonies a few miles away, from which they’ll gather baseline data.

Several varieties of plants are being grown in an enclosed greenhouse near the test site. The plants’ soil is tainted with varying levels of TNT so the researchers can study how efficiently the plants uptake the chemical.

‘There is very little written in the scientific literature about plant uptake of explosive contaminants,’ says Sandia’s Susan Bender. ‘We are conducting new studies to see if plants rooted in TNT-tainted soil will take up the residues into their roots, stems and flowers, and even incorporate them into their pollens.’

If plants that readily accumulated the TNT could be identified, a suspected minefield could be seeded with those plants (by air) to maximize the bees’ chances of finding the mines.

Inside the greenhouse a small colony of bumblebees has been established to measure how efficiently the bees carry TNT-tainted pollen and soil back to the hive. The results from controlled environments will be compared with the results obtained in the field to see how well the bees are doing.


Chemists Susan Bender and Phil Rodacy of Sandia National Laboratories check uptake rates of TNT by several varieties of plants being grown in a greenhouse

Bromenshenk and a team of colleagues and students plan to work at Sandia. New colonies of honey bees will be introduced at the test minefield. The Montana team will use highly instrumented ‘honey bee condos’, which automatically count the number of times bees fly in and out of the hive, to track the bees’ flight activity. Subtle changes in flight activity and other bee behaviours have been shown to signal that the bees are being exposed to environmental contaminants.

Pollen, dust, air and other samples collected by the bees and brought to the hive will be analysed for trace amounts of explosives. Sandia will examine the samples using highly sensitive chemical analysis tools to determine whether the bees can reliably indicate the presence of landmines in an area over time.

One goal of ongoing tests at Montana is to determine which explosives bees can smell and then train them to seek those chemicals. If bees can be trained to associate the odour of explosives (such as TNT) with food (sugar syrup, for instance), the bees may spend more time near plants and surface soils contaminated with TNT, increasing the odds that they would bring back TNT residues from an area that contains buried mines.

Bromenshenk has demonstrated that by providing a new bee colony with feeders containing traces of a marker chemical, then gradually moving the feeders farther from the hive and eventually removing them, bees can be trained to forage wherever they smell the chemical.

If bees can be trained to seek TNT, the Montana team may attach small diodes onto the backs of several hundred TNT-trained bees. Then, using a handheld radar tracking device, they will chart where those bees go to determine whether they tend to forage near the locations of known landmines.


The ultimate goal of the project is to determine whether buried mines are present in large areas by establishing beehives near the suspected mines, monitoring bees’ flight activity and analysing hive samples. If this method works and it is reliable, people could be given the green light to re-enter or farm large areas, based on bee sampling.

Apart from their accuracy, bees have a number of strong advantages when it comes to land mine detection. As lightweight hoverers, they can cover an area without accidentally discharging a mine. They are much cheaper than high-tech equipment and they are much easier to train than dogs and other mammals. Amazingly, bees from one hive will recruit others, so only one trained hive is needed to start surveying a large area.

Last year funding was not forthcoming to move the tests overseas – a crucial step needed to explore conditions in actual minefields. With the new Obama administration dedicated to more federal funds for scientific research, there’s a chance that the research will resume soon and negotiations are underway on arrangements for a new round of trials.

‘The beauty of this approach is that bees are indigenous to every climate on earth and there are beekeepers everywhere,’ Bender says. ‘And you wouldn’t need a million-dollar piece of equipment and extensive training to use it. The countries where landmines are a problem typically don’t have those kinds of resources.’


The work is funded by the Defense Advanced Research Projects Agency’s (DARPA) Controlled Biological Systems Program. This supports research of sentinel species (such as bees, wasps, caterpillars and moths), biohybrids (robotic systems that make use of animal features) and robotic systems for detection of contaminants and other environmental variables.

Sandia National Laboratories: Jerry Bromenshenk:

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