Schmidt sting pain index

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The Schmidt sting pain index is a pain scale rating the relative pain caused by different hymenopteran stings. It is mainly the work of Justin O. Schmidt (born 1947), an entomologist at the Carl Hayden Bee Research Center in Arizona. Schmidt has published a number of papers on the subject, and claims to have been stung by the majority of stinging Hymenoptera.

His original paper in 1983 was an attempt to systematize and compare the hemolytic properties of insect venoms.[1] The index contained in the paper started from 0 for stings that are completely ineffective against humans, progressed through 2, a familiar pain such as a common bee or wasp sting and finished at 4 for the most painful stings. Synoeca septentrionalis, along with other wasps in the Synoeca genus, bullet ants and tarantula hawks were the only species to attain this ranking. In the conclusion, some descriptions of the most painful examples were given, e.g.: "Paraponera clavata stings induced immediate, excruciating pain and numbness to pencil-point pressure, as well as trembling in the form of a totally uncontrollable urge to shake the affected part."

Subsequently, Schmidt has refined his scale, culminating in a paper published in 1990, which classifies the stings of 78 species and 41 genera of Hymenoptera. Schmidt described some of the experiences in vivid detail.[2]

An entry in The Straight Dope reported that "implausibly exact numbers" which do not appear in any of Schmidt’s published scientific papers were "wheedled out of him" by Outside magazine for an article it published in 1996.[3]

In September 2015 Schmidt was co-awarded the Ig Nobel Physiology and Entomology prize with Michael Smith, for their Hymenoptera research.[4]

Overview[edit]

Schmidt's pain scale of Hymenopteran stings is organized into levels, ranging between below 1 to 4, with 4 being the most painful. However, insect stings that feel very differently can be put into the same level. Thus, Schmidt always includes a brief description of his experience being stung by each type of insect.[5] On that note, these stings are based on Schmidt's subjective perspective, and insect stings can vary person to person, so the scale is not universal.[6]

Pain Level 1[edit]

Some of the insect stings Schmidt considers to be at a pain level of 1 include the Southern fire ant, the Elongate twig ant, the Western paper wasp, the white-faced bee, and most small bees. The duration of the pain of insect stings categorized into Pain Level 1 generally is five minutes or less.[7]

Since many small bees are categorized into a pain level of 1, it should be noted that the most toxic polypeptides in bee venom are melittin, apamin, and MCD peptide. Melittin is the main toxin of bee venom, and it damages red blood cells and white blood cells. Apamin is a neurotoxin that augments polysynaptic reflexes. MCD peptide destroys mast cells.[8]

Feeling only slight pain, Schmidt has described the sting of the Anthophorid bee, categorized into Pain Level 1, as “almost pleasant, a lover just bit your earlobe a little too hard.”[5] Also rated into Pain Level 1, Schmidt has described the sting of the sweat bee[disambiguation needed] as "light, ephemeral, almost fruity. A tiny spark has singed a single hair on your arm."[6]

Pain Level 2[edit]

Schmidt sets the sting of the Western honey bee at a pain level of 2 to be the anchoring value, basing his categorization of all other stings off of it.[5] He has categorized a variety of wasps, bees, and ants into Pain Level 2, including the yellowjacket, the Asiatic honey bee, and the trap-jaw ant. The duration of the stings in this level is generally between five to ten minutes long. Schmidt categorized the majority of Hymenopteran stings as having a pain level of 2.[7]

The sting of a termite-raiding ant, categorized as a pain level of 2, has a similar feeling as "the debilitating pain of a migraine contained in the tip of your finger," according to Schmidt.[5] On the contrary, the yellowjacket's sting was described as being "hot and smoky, almost irreverent. Imagine W. C. Fields extinguishing a cigar on your tongue." Though the sting was a different feeling, the yellowjacket was also rated at a pain level of 2.[6]

Pain Level 3[edit]

Most insects that are characterized as having a pain level of 3 are wasps, including the red paper wasp, the metricus paper wasp, and the velvet ant (which is actually a wasp, not an ant). The duration of the sting pain can range anywhere from one minute (such as the sting of the red paper wasp) to half an hour (such as the sting of the velvet ant).[7] Wasp venom uniquely contains wasp kinin that exhibit kininlike activity. One of the kinins found in wasp kinin, polistes kinin 3, is found to lead to similar effects on smooth musculature and circulation as bradykinin.[8]

Some ants are also rated at a Pain Level 3, including the giant bull ant and the Maricopa harvester ant. Schmidt considered the sting of the Maricopa harvester ant as having a pain level of 3, describing it as such: “After eight unrelenting hours of drilling into that ingrown toenail, you find the drill wedged into the toe.”[5]

Pain Level 4[edit]

Pain Level 4 is the highest level in the Schmidt sting pain index. Schmidt gave the sting of the tarantula hawk a rating of a 4, which he described as "blinding, fierce [and] shockingly electric."[9] The composition of the tarantula hawk sting is unknown, though the duration of the sting is short-lived, lasting only approximately 5 minutes.[7]

Schmidt rated the sting of the bullet ant as a 4-plus.[10] This sting can last between 5 to 24 hours.[7][11] Schmidt has described the sting as "pure, intense, brilliant pain...like walking over flaming charcoal with a three-inch nail embedded in your heel."[10] The bullet ant's venom primarily contains poneratoxin, a paralyzing neurotoxic peptide.[12]

Schmidt has considered the stings of the tarantula hawk and the bullet ant to be the most painful stings.[7]

Evolution from painful to toxic stings[edit]

The Schmidt Sting Pain Index arose from the pursuit of a larger hypothesis: that the evolution of sociality in Hymenoptera was dependent on the evolution of venom that was both painful and toxic.[13] Pain is an advertisement of damage in the body, but molecules that produce pain and those that are toxic, and actively cause damage, are not the same. Although the painful signal acts as a deterrent, intelligent predators will learn the dishonesty of this signal with repeated exposure – that there is no real damage being done.[14] For the early Hymenoptera that were primarily solitary, the pain alone would allow them the chance to escape. Furthermore, solitary insects do not provide a high energy reward for predators, and therefore predators do not expend significant effort to hunt them. However, with the evolution of sociality where many Hymenoptera cluster together in colonies, nests become a nutritionally rich and therefore worthwhile target.[15] If there were no defenses, predators would devour the defenseless society, leaving few surviving individuals and eliminating social reproduction.[14] Sociality would therefore not be beneficial. In order for sociality to evolve, Hymenoptera needed a defense beyond a painful sting to protect their whole colony. Their sting was an advertisement of damage, and toxicity evolved as its truth. With a toxic sting, and thus the ability to protect against predators, Hymenoptera were able to progress towards sociality and its associated evolutionary benefits of the shared raising of youth, individual task specialization, inter-colony communication, and food storage.[15]

To approach studying this evolutionary connection between toxicity and sociality, Schmidt recognized there needed to be a quantitative measure with which to score the painfulness of stings. Assays for toxicity are already well characterized and can be quantified, but without the Schmidt Sting Pain Index, there would be no way to relate the amount of sociality to the level of pain, and therefore this hypothesis could not have been studied.[16]

See also[edit]

References[edit]

  1. ^ Schmidt, Justin O.; Blum, Murray S.; Overal, William L. (1983). "Hemolytic activities of stinging insect venoms". Archives of Insect Biochemistry and Physiology. 1 (2): 155–160. doi:10.1002/arch.940010205. 
  2. ^ Schmidt, Justin O. (1990). "Hymenoptera Venoms: Striving Toward the Ultimate Defense Against Vertebrates". In D. L. Evans; J. O. Schmidt. Insect Defenses: Adaptive Mechanisms and Strategies of Prey and Predators. Albany, New York: State University of New York Press. pp. 387–419. 
  3. ^ Cecil Adams (May 11, 2012) Did the creator of the Schmidt Sting Pain Index volunteer to get stung by everything on earth?, The Straight Dope
  4. ^ Webb, Jonathan (18 September 2015). "'Universal urination duration' wins Ig Nobel prize". BBC. 
  5. ^ a b c d e Steinberg, Avi (18 August 2016). "The Connoisseur of Pain". The New York Times Magazine. 
  6. ^ a b c Wrenn, Eddie. "The 10 most painful stings on the planet, by the self-sacrificing man who tried 150 different varieties in the name of science". Daily Mail Online. 
  7. ^ a b c d e f Schmidt, Justin (1990). "Hymenopteran venoms: striving toward the ultimate defense against vertebrates". Insect defenses: adaptive mechanisms and strategies of prey and predators. Albany: State University of New York Press. pp. 387–419. 
  8. ^ a b Habermann, E. (28 July 1972). "Bee and Wasp Venoms". Science. 177 (4046): 314–322. doi:10.1126/science.177.4046.314. 
  9. ^ Schmidt, Justin; Blum, Murray; Overal, William (1983). "Hemolytic activities of stinging insect venoms". Archives of Insect Biochemistry and Physiology. 1 (2): 155–160. doi:10.1002/arch.940010205. 
  10. ^ a b Loria, Kevin (23 August 2016). "A man who has been stung more than 1,000 times reveals the one bug you really want to avoid". Business Insider. 
  11. ^ Gough, Zoe (13 March 2015). "The world's most painful insect sting". BBC Earth. BBC. 
  12. ^ Szolajska, Ewa; Poznanski, Jaroslaw; Ferber, Miguel López; Michalik, Joanna; Gout, Evelyne; Fender, Pascal; Bailly, Isabelle; Dublet, Bernard; Chroboczek, Jadwiga (2004). "Poneratoxin, a neurotoxin from ant venom". The FEBS Journal. 271 (11): 2127–2136. doi:10.1111/j.1432-1033.2004.04128.x. 
  13. ^ Steinberg, Avi (18 August 2016). "The Connoisseur of Pain". Retrieved 7 May 2017. 
  14. ^ a b Schmidt, Justin (2016). The Sting of the Wild. Baltimore, Maryland: Johns Hopkins University Press. ISBN 978-1-4214-1929-9. 
  15. ^ a b Schmidt, Justin (22 March 2014). "Evolutionary responses of solitary and social Hymenoptera to predation by primates and overwhelmingly powerful vertebrate predators". Journal of Human Evolution. 71: 12–19. 
  16. ^ Conniff, Richard (10 August 2009). "Oh, Sting, Where Is Thy Death?". Retrieved 7 May 2017. 

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