A few weeks ago I was stung by a wasp. The pesky creature somehow managed to work its way through the vent in my shirt sleeve and then got itself stuck. As I might have done in similar circumstances it panicked and in its anxiety to find a way out it stung me. Jolly painful it was too. I managed to realise what was going on before it had chance to strike again and, I regret, in an uncharacteristic lapse into an un-Zen-like state, I killed it.
It was a surprise to me to learn that there is such a thing as the Schmidt Sting Pain Index which rates, using the honeybee as a reference point, the painfulness of a sting from one of 78 carefully selected species of hymnoptera – bees, ants, wasps and the like to you and me. Schmidt worked out a scale running from 0 to 4, nought being awarded to a creature that packed a sting that wasn’t capable of breaking the skin and a massive 4, as they say on game shows, to the most painful stings known. Only the bullet ant and the tarantula hawk scored a perfect 4 – forearmed is forewarned, they say.
That’s all very well and useful for consoling yourself that your temporary pain could have been so much worse if you had encountered a bullet ant in full flow but, as Michael L Smith of Cornell University realised, that is only half the story. Surely, the sensation of pain will vary depending upon where in the body you were stung and, if that were the case, there could be no absolute value allocated to the sting of any one of the hymnoptera family. So, as is the way with scientists he decided to conduct an experiment to establish whether and how pain varies depending on sting location.
The way he chose to experiment was to take the humble honeybee or a number, I would imagine, and get them to sting one of twenty five selected body parts. Research thrives on volunteers willing to help the people in white coats extend the limits of human knowledge but for some unaccountable reason, Smith couldn’t find any and so conducted the experiments on himself.
If I remember my chemistry you need to describe your methodology when recounting an experiment and Smith’s was fairly simple. He held the bee against the part of the body to be tested until the sting was first felt, then kept it there for 5 seconds, pulled the bee away leaving the stinger in place where it remained for 1 minute before being removed with tweezers. Of course, by this time the honeybee is dead. Smith devised a scale running from 1 to 10 to determine or describe the intensity of the pain in any given body part and each part was stung three times. The pain rating for each location was averaged over the three rounds and ranked according to score. As Smith drily observed in his paper, “all the stings induced pain in the author” .
The clear message from this research is that pain really does vary according to where you are stung. The lowest ranked places were the skull, middle toe and upper arm, all scoring 2.3, whereas the most painful parts were the nostril (scoring 9.0), the upper lip (8.7) and the penis shaft (7.3). Armpit, cheek, palm and scrotum all scored 7. If you are looking to enjoy a 5, then you need to be stung on the foot arch, forearm or back of the knee.
This is really handy to know but we are reliant upon Smith’s pain threshold being roughly in line with our own. I think we need more data. Any volunteers?