The Untold History Of Insect Warfare

The term "biological warfare" typically conjures up images of viruses, bacteria, and HAZMAT suits. But biological warfare can also refer to the use of insects as a weapon, although sometimes, that weapon can also incorporate diseases as well. In general, the use of insects in war has largely been experimented on rather than actually being implemented. But on more than one occasion, insects have found themselves participating in battles in which they have absolutely no stake.

Logistically, using insects in war poses more problems than clear-cut victories. Insects are hard to keep track of and as several experiments would go on to show, once insects are released into the world it can be incredibly difficult to collect them all back. As a result, insect warfare can affect the ecosystem in previously unknown ways, which makes the risk of using them far greater than any potential reward.

And yet, scientists and governments continue to experiment with insects and their potential as fighting combatants. And some of the experiments done by the U.S. military even remain largely classified to this day, so it's difficult to know exactly the full ecological effect of all their entomological tests. At the end of the day, although it's not comparable to a biblical plague of locusts, the use of insects in war can be equally devastating. This is the untold history of insect warfare.

As the Black Death spread during the 14th and 15th centuries, the bubonic plague was also used as a weapon, though because it was unknown at the time that fleas were the vector for the bubonic plague, the disease was transmitted using another host instead. Both the cities of Kaffa, Crimea and Karlštejn, Czech Republic witnessed infected human cadavers catapulted over the walls during sieges. And according to Army Chemical Review, it's believed that the refugees who fled Kaffa in 1348 "may have initiated the second plague pandemic that seeded throughout Europe."

As the flea was recognized as a vector of plague by 1911, Japan started experimenting with plague-infected fleas during the Second World War. There were several facilities where Japan conducted biological warfare experiments, but Unit 731 is considered the most notorious.

After developing a bomb filled with plague-infected fleas, Japan tested it by dropping it in Ningbo and Changde in China. But NPR writes that these tests were just a precursor for what was known as Operation Cherry Blossoms at Night, which entailed dropping plague-infected fleas into California. However, the plan was narrowly avoided only because Japan surrendered on September 2, 1945, and Operation Cherry Blossoms at Night had been scheduled for September 22. Had World War II continued for just a few weeks more, there would've likely been a plague outbreak in California.

During the Korean War, the United States was accused of engaging in insect warfare in North Korea. According to Montana State University, Chinese entomologists claimed that the U.S. military was spreading "disease-carrying anthomyiid flies, springtails, and stoneflies with P-51 fighters." There were also accusations that the United States spread plague-infected rats and anthrax-infected flies and spiders.

The Cold War International History Project writes that the Chinese and North Korean governments set up two "international commissions" in order to investigate these claims. While the commission found that the United States "probably did engage in limited biological warfare," the United States insisted that the commission was just a communist front and a disinformation campaign.

But although the United States continues to maintain that insect warfare was never used in North Korea, in 2019, the House of Representatives voted to look into whether or not these claims were truly disinformation or not. Roll Call reports that New Jersey Republican Christopher H. Smith's amendment to the 2020 Defense Authorization Bill would've required the Pentagon inspector general to conduct a review of whether or not the U.S. military had experimented "with ticks and other insects regarding use as a biological weapon between the years of 1950 and 1975." Unfortunately, it didn't pass the Senate, and the Senate has repeatedly refused to pass the provision in subsequent defense authorization bills.

In 1955, the U.S. military moved on to experimenting with mosquitos in Operation Big Buzz. According to "Six-Legged Soldiers" by Jeffrey A. Lockwood, Operation Big Buzz was a "simulated, mosquito-based attack," in which hundreds of thousands of mosquitos were dropped into rural Georgia. Up to one million Aedes aegypti mosquitoes were raised and in May 1955, a third of the mosquitos were dropped onto rural Georgia in E-14 munitions. The rest of the mosquitos were used in "loading and storage tests." And while the military hoped to see the efficacy of spreading yellow fever through mosquitos, the mosquitos were uninfected for the test.

Guinea pigs were used to determine the success of the test, as were human volunteers. And after the mosquitos managed to find hosts "nearly a half-mile downwind," the experiments were considered to be "a rip-roaring success."

According to a March 1981 Army report, the military estimated that it would cost roughly $27,000 ($131,900 today) to launch a yellow-fever infected mosquito attack on a battalion and approximately 225,000 infected mosquitoes would be required. And this was seen as being more cost-effective than an aerosol attack. Cost analyses were also run to see how much a yellow fever-infected mosquito attack on a city would cost. And achieving a 50% mortality rate, the most cost effective one, would only cost 29 cents per death ($1.42 today).

Mediterranean fruit flies, also known as Medflies, were first sighted in California in 1975 and by the 1980s, there were multiple eradication programs aimed at the medfly. Between 1975 and 1993, California spent over $170 million on medfly eradication efforts. SFGate writes that the medfly caused "millions of dollars in damage" to various crops and in response, Governor Jerry Brown decided to spray Malathion from helicopters to suppress the medflies.

The infestation of 1989 was notably different from the previous medfly outbreaks. The U.S. Department of Agriculture noted that there were more female medflies than male medflies and there was an absence of the number of larvae one would expect from the number of adults. Plus, "farmers kept finding medflies right outside spray zones."

In December 1989, California state senators, newspapers, and the mayor of Los Angeles received a letter from a group that called themselves The Breeders, taking responsibility for the medfly outbreak. The letter claimed that the group was releasing medflies in order to halt the spraying of Malathion and "Every time the copters go up to spray, we'll go into virgin territory or old Medfly problem areas and release a minimum of several thousand blue-eyed Medflies. We are organized, patient, and determined." Although the USDA tried to make contact with The Breeders, they reportedly got no response. And at the end of the day, Malathion spray stopped being used, and instead, the state started "introducing sterile flies into the population."

As gene-editing is being used to make plants more resistant to disease, the U.S. Defense Advanced Research Project Agency (DARPA) has been looking into using insects as a vector for gene-editing. According to Wired, as part of a program called Insect Allies, DARPA is researching how to use insects to deliver the viruses needed to genetically edit crops in the field.

However, many biologists and ethicists argue that "this new technology poses a biosafety risk and could easily be turned into a new kind of biological weapon." And there are also functional issues with this, since gene-editing through an insect is undoubtedly going to be imprecise and it'd be almost impossible to guarantee that all the plants were being edited in the same way. And unfortunately, no matter how promising research can look, "it's always easier to make it a weapon," notes Guy Reeves, a biologist at the Max Planck Institute for Evolutionary Biology.

According to Entomological "Weapons" of Mass Destruction by Thomas F. Moore, scientists are also experimenting with editing the genomes of mosquitos, ultimately towards incapacitating the mosquitos to prevent the spread of disease. In doing so, scientists created "a yellow, three-eyed, wingless version." And although scientists see this as the potential towards eradicating the spread of disease by mosquito, this research also "reveals how the genetic code might also be corrupted to do harm in living organisms."