Do you remember the last time you were stung by a bee? What did it feel like? Would you say it hurt more than being stung by a wasp? For one scientist, these are more than just idle questions. Justin Schmidt is an entomologist working at the Carl Hayden Bee Research Center in Arizona. He specializes in hymenopteran insects, the group that includes bees, wasps, and ants. Throughout his research, he’s traveled the world, studying these insects in their native environments. Unfortunately, they are not always the most cooperative subjects.

According to Schmidt, he has been stung over 1,000 times by the insects he’s interested in, including almost every stinging species in the Hymenoptera order. Rather than saying “ow” and reconsidering his line of work, Schmidt began to do something different with these painful experiences: He documented them, and created what is now known as the Schmidt sting pain index.

Schmidt sting pain index

The Schmidt sting pain index classifies each insect sting on a scale of 0 to 4. Insects whose stings are at the 0 level are ineffective to humans, not causing pain at all. Insect stings graded as 4 are the most painful, reserved for insects that can induce blistering agony in their unlucky human victims. Many people have been stung by honey bees, so Schmidt considers them the main reference point on the pain index, at a 2. Still, there is a lot about the sensation of being stung by an insect that a simple number cannot convey. This is why, with each sting he records, Schmidt also includes an evocative, almost poetic description of what it felt like.

For a fire ant, a 1.2 on the pain index, he says “sharp, sudden, mildly alarming. Like walking across a shag carpet and reaching for the light switch.” Something a little more painful is the termite-raiding ant, a level 2: “The debilitating pain of a migraine contained in the tip of your finger.” Red harvester ants come in at a hearty 3. "Bold and unrelenting. Somebody is using a drill to excavate your ingrown toenail,” reports Schmidt in their regard.

The dreaded tarantula hawk wasp, whose sting is "blinding, fierce, and shockingly electric." Image by Robert DuHamel.

What sorts of insect merit a 4 on the pain index? Schmidt ranks the tarantula hawk, the bullet ant, and the warrior wasp to possess the most painful stings he’s ever received. The suffering is vividly portrayed in his descriptions of the sensations. He describes the warrior wasp sting as "torture. You re chained in the flow of an active volcano. Why did I start this list?"

Why indeed?

Schmidt isn’t cataloging painful insect stings for fun. In fact, he says that almost every sting he’s ever received has been an unintentional result of his research. He collects samples of various stinging insects for another purposes: Trying to tease out the biology and evolution of the sting itself.

It’s simple enough to understand that insects sting as a defensive measure, but there’s more to it than that. For one thing, though the concept and delivery mechanism for stinging may be similar among different insect species, there are actually a wide variety of different chemicals used. Stinging has evolved many different times among insects, leading to equally many different chemical strategies employed.

Insects that evolve stinging tend to have something in common: A social lifestyle. Insects that gather in colonies or hives make a tempting target for predators looking for an easy meal. Insects are much smaller than the animals trying to eat them, so painful stings are a way to even the odds. Being able to pack a punch also allows insects like honeybees to utilize high value resources like flowers without as much danger of predation.

In a case of truly amazing scientific timing, I was actually stung by a bumblebee during the week that I was working on this blog. Considering that a honeybee sting is a 2 on the pain index, I classify the bumblebee sting as a 1.7, and describe my experience as “sudden and disruptive. Lemon juice in a papercut you’d forgotten about.”

I can’t find any indication of whether the bumble bee is on Schmidt’s pain list, so you’ll just have to take my word for it!

- Kate Dzikiewicz, Paul Griswold Howes Fellow