Bees have been used as weapons for defense for thousands of years. One of the earliest historical accounts (first century B.C.) that mentions bees being used against enemies involves the Heptakomotes of Asia Minor (present-day Turkey) and Pompey the Great. With the aid of their bees, the Heptakometes knew that when bees gather pollen from such plants as rhododendron the honey produced is loaded with alkaloids which are harmless to bees but toxic to humans. They were able to obtain and leave a cache of poisoned honey in the path of 1000 advancing Roman soldiers.
During that time, gains from raiding and looting were part of a soldier’s pay, so the Romans naturally seized the honey and consumed it. They were soon deathly ill, and in no shape to resist the attack that followed.
The Romans also used bees, but in a more direct manner. They would catapult beehives at enemy positions. In medieval times, castles were often designed and built with bee hives within the walls.
Years later, bees also played a part in the Civil War. During the Battle of Antietam, attacking Federal troops advancing through a farmyard were routed, not by the heavy gunfire they faced, but by enraged bees from hives shattered by Confederate artillery fire. There’s also a well-known case of British troops, in action in German East Africa during WWI, encountering maddened bees, but as at Antietam, the bee attacks seem to be accidental.
During the Vietnam War, Viet Cong guerillas were masters of improvised weaponry, and before attacking, were known to lob 30 or more nests of hornets and wasps into military outposts.