Which Insect Has the Most Toxic Venom?

Hopefully, in your lifetime you will never experience the painful sting of a bee, be swarmed by biting ants or brush your hand against the spines of a stinging caterpillar. Among the venomous insects, some possess only mildly toxic venom, while others pack a serious punch capable of taking down a threat as large as a person.

The insect with the most toxic venom is not necessarily the most painful or the most lethal. Pain is a fairly subjective measure. What I find excruciating, you might tolerate as merely uncomfortable. We can't compare venom on the basis of morbidity statistics, either, since people's immune systems respond differently to the same venom. For those with bee venom allergies, a bee sting can be deadly, though the venom itself is not that toxic.

To compare insect venoms and determine which is the most toxic, we need an objective way to measure them. A standard measure used in toxicology studies is the LD50 or median lethal dose. This measurement determines the amount of a toxin, relative to body weight, that is required to kill exactly half of a given population of organisms. In this case, researchers tested insect venom on mice to compare and rank their toxicity.

So which insect came out on top? The harvester ant, Pogonomyrmex maricopa. With an LD50 measurement of just 0.12 mg per kg of body weight, the harvester ant venom proved far more toxic than that of any bees, wasps, or other ants. By comparison, honey bee venom has an LD50 measure of 2.8, and a yellowjacket's venom has an LD50 of 3.5 per kg of body weight. Just 12 stings from the venomous harvester ant were enough to take out a 2 kg animal.

Reference: W.L. Meyer. 1996. Most Toxin Insect Venom. Chapter 23 in University of Florida Book of Insect Records, 2001.