Where's the worst place for a bee sting? One scientist found out...

What's the worst place to be stung on your body? One fearless researcher took it upon himself to find out.

There is a long and noble history of self-sacrifice in scientific research. Isaac Newton famously inserted metal needles into his eye socket to discover what effect manipulating the eyeball had on vision, and forced himself to stare at the sun for minutes on end.

Graduate student Michael Smith, from Cornell University in New York, was interested in the different levels of pain experienced due to insect stings depending on where on the body one is stung. So, naturally, he decided to find out what hurt the most - using his own body as a test subject.

Working at the department of Neurobiology and Behaviour, Smith was inspired to begin his research when a honeybee flew up inside his shorts and  stung him on the testicles, according to an interview with National Geographic.

'I was really surprised that it didn't hurt as much as I thought it would', Smith told National Geographic. He went away and developed his masochistic plan to receive stings all over his body.

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His paper begins by asking 'If sting location is important in pain perception, how important is it?' He chose the European honey bee as a source of stings that 'can be reliably provoked'- noting also that it ranks halfway up the Schmidt pain scale.

The Schmidt pain scale is an index compiled by similarly reckless entomological researcher Justin Schmidt, who between 1984 and 1990 catalogued the severity of stings from insects in the order Hymenoptera - a group that includes bees, wasps, ants and hornets.

Schmidt's work is fascinating in its description of pain - which we will return to - but it makes no effort to catalogue pain responses across the body. Enter Smith and his honey bees.

Smith did not hold back in his research. He wryly notes that 'Cornell University’s Human Research Protection Program does not have a policy regarding researcher self-experimentation, so this research was not subject to review from their offices. The methods do not conflict with the Helsinki Declaration of 1975, revised in 1983. The author was the only person stung, was aware of all associated risks therein, gave his consent, and is aware that these results will be made public.'

He did not hold back in his research, choosing 25 locations on the body and using his forearm as a benchmark, giving stings received there a score of five out of 10. Stings elsewhere were then compared with the forearm, ranging from 1-10.

Smith stung himself five times a day between 9am and 10am for 38 days, waiting five minutes between stings. He stung his palm, armpit, back of the knee, nipple and behind his ear, among other places.

And the most painful? Inside the nostril, apparently - followed by the upper lip and, apparently, the 'penis shaft'. Smith described the nostril sting, which he rated 9.0 out of 10, as 'electric and pulsating. Getting stung in the nose is a whole-body experience'.

Originally intending to include stings to his eyes in the study, Smith was dissuaded by his supervisor, who feared he might go blind.

The details of the study are wince-inducing. Smith writes that 'The bee was held against the sting location until the sting was first felt, and kept at the location for five seconds to ensure that the stinger would penetrate the skin.'

Smith's results state dryly that 'All the stings induced pain in the author'. His least painful places were the skull, tip of his third toe, and the upper arm (all of which he rated at 2.3 out of 10).

The variation in pain couldn't be fully explained either by number of nerve endings or thickness of skin. Smith notes that stings to the palm were much more painful than the skull or upper arm, both of which have thinner skin, and pain levels between the upper lip and the middle finger, which have similar levels of sensitivity, were very different.

Smith does emphasise that his experiences are subjective, but feels that the overall responses would be similar. 'If someone else did this, they'd probably have different locations that they felt were worst'.

Justin Schmidt's work in the late 1980s is one of the most comprehensive studies of insect sting pain. He rated several of the world's most fearsome stinging insects by the type and severity of pain they delivered, keeping almost poetic notes.

Some of his descriptions include: 'Light, ephemeral, almost fruity. A tiny spark has singed a single hair on your arm' - the Sweat bee (rated 1.0 out of 4)

'A rare, piercing, elevated sort of pain. Someone has fired a staple into your cheek.' - the Bullhorn acaci ant (1.8)

'Caustic and burning. Distinctly bitter aftertaste. Like spilling a beaker of hydrochloric acid on a paper cut' - the Paper wasp (3.0)

'Blinding, fierce, shockingly electric. A running hair drier has been dropped into your bubble bath' - the Tarantula Hawk (rated 4.0 out of 4 for pain)