I carried out my first experiment with a stinging insect when I was seven, picking a honey bee off a dandelion and placing it on the arm of my teacher. My hypothesis was that it might sting her, and it turned out to be correct, much to her dismay.

Where I grew up, in the Appalachian area of the north-east US, we had lots of honey bees and wasps of various sorts. As a kid, I was stung by virtually all of them. I realised that they registered the same sort of pain – the intensity may vary from one to the next, but they were fairly similar. But an accidental run-in with a colony of harvester ants led to a life-changing revelation: they didn’t feel at all as I expected they would. They really hurt.

Twenty years on, working as a chemical ecologist, I was still fascinated by the defence mechanisms of wasps, bees and ants. As part of my job studying interactions between insects and their environment, I did fieldwork that involved collecting different species, providing endless opportunities to get stung. It occurred to me that while the venom could be analysed, it was harder to make comparisons between the type of pain each insect caused, which seemed crucial in understanding how and why different types of sting had evolved.

Insects that live in areas with the greatest number of fierce predators tend to be the most aggressive, and their stings are the most potent. To test this, I came up with a pain index, where the level of discomfort is measured on a scale of one to four. Whenever I was stung, I would rate the pain, then write a description. At the lower end of the scale, a one, I put the sweat bee, which I describe as: “Light, ephemeral, almost fruity. A tiny spark has singed a single hair on your arm.” The twos include the yellowjacket wasp. “Hot and smoky, almost irreverent,” I wrote. The red harvester ant (“Bold and unrelenting. Somebody is using a drill to excavate your ingrown toenail,”) scores a three. But nothing comes close to the bullet ant. Some insects inflict similar levels of suffering in the short-term: the pain caused by tarantula hawk wasps lasts about two minutes; warrior wasps, about an hour. But neither can manage the 24 hours of agony a bullet ant can deliver.

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My encounter with these queens of sting (only females have the ability to inflict pain) took place in Brazil. I was working with a field assistant tough enough to cup a wasp’s nest in his bare hands, but I couldn’t get him near the bullet ant colony. It was only when they started boiling out of the ground that I realised why. Before I knew it, they were on my finger, and I was stung. The pain slammed into me like a freight train, instant and overwhelming. I started to lose coordination and my hand wouldn’t stop shaking. In the index, I describe the pain as: “Pure, intense, brilliant… Like fire-walking over flaming charcoal with a three-inch rusty nail grinding into your heel.” Bullet ants got their name because their sting is said to be analogous to getting shot, but their venom isn’t designed to do long-term physical damage. Knowing that I just had to sweat it out, I retired to a bar, where I tried to ease the suffering with beer and ice. After 18 hours, I fell into an exhausted sleep.

There have been other mishaps during my research. Once, while moving a colony of bees, I was stung 20 or 30 times on my hand, which swelled up like a hockey mitt. In Costa Rica, I had venom sprayed into my eyes by paper-nesting wasps while trying to remove their nest from a tree. It took several minutes of frantic blinking to restore my sight.

If I am stung by an insect I have never encountered before, I still update the pain index, which was recently published in full for the first time – after 35 years, I have been stung by 150 species of insect and covered most that interest me.

Family members love what I do – my wife has even performed Chinese folk songs celebrating stinging insects, and my son is always ready to go on adventures to seek out specimens. I know some people think me crazy, but I am no masochist, and only occasionally am stung on purpose. When it does happen, I initially react as anyone else would – cursing, more than I should admit. Then I get out my notebook and stopwatch, sit down and make notes.

• As told to Chris Broughton. Do you have an experience to share? Email experience@theguardian.com

The standfirst of this article was amended on 11 May 2018. It should have said bullet, not bull, ants