The Schmidt Sting Pain Index rates the painfulness of 78 Hymenoptera species, using the honey bee as a reference point. However, the question of how sting painfulness varies depending on body location remains unanswered.
This study rated the painfulness of honey bee stings over 25 body locations in one subject (the author). Pain was rated on a 1–10 scale, relative to an internal standard, the forearm. In the single subject, pain ratings were consistent over 3 repetitions (Table 1).
Sting location was a statistically-significant predictor of the pain rating in a linear model (p < 0.0001, DF = 25, 94, F = 27.4). The 3 least painful locations were the skull, middle toe tip, and upper arm (all scoring a 2.3). The 3 most painful locations were the nostril, upper lip, and penis shaft (9.0, 8.7, and 7.3, respectively).
This study provides an index of how the painfulness of a honey bee sting varies depending on body location.
…Method: 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.
25 sting locations were selected throughout the body (see Figure 1). One location (forearm) was selected as an internal standard, with the a priori assumption that stings to the forearm would induce a median level of pain. The author self-administered 5 stings per day. The first sting and last sting were the internal standards (forearm). These stings were given a score of “5”, and the 3 “test” stings were rated relative to the pain of the forearm stings. All stings occurred 9AM–10AM, to avoid time of day effects. At least 5 min of delay was given between stings, longer if pain from the previous sting persisted. The pain was rated by the author as precisely as possible on a scale of 1–10, relative to the internal standard (score of 5). Lower scores denote less pain; higher scores denote more pain. A numerical rating scale was used to simplify comparisons between sting locations. Previous research has found that numerical rating scales are the most responsive relative to other pain scales (Ferreira-Valente et al 201113ya).
…Sting locations were randomly ordered by the statistical program R (R Core 2012). When applicable, the left and right side of the body were alternated. Some locations required the use of a mirror and an erect posture during stinging (eg. buttocks). Stinging occurred before the author did any other honey bee work, to prevent unintentional stings during routine bee work from interfering with the experimental stings. The author had received ~5 stings per day for 3 months before the experiment, so no changes in his immune system were to be expected over the course of the experiment (Light et al 197549ya).
…In total, 3 full stinging rounds were conducted at the Liddell Field Station of Cornell University in Ithaca, New York (42°27.6′N, 76°26.7′W). The author was stung over a total of 38 days, between 20 August 2012 and 26 September 2012. To keep the author as blind to the ratings as possible, notes were kept hidden from previous days. After two stinging rounds had been conducted (each stinging round covered all anatomical sting locations), the scores were reviewed, to see if there was a large discrepancy between scorings per sting location. Only one location differed by 3 units (foot arch), and two locations by 2 units (upper thigh and behind the ear). Even though the consistency between the first two rounds was high, a third round of stinging was performed.
…The 3 most painful sting locations were the nostril, the upper lip, and the penis shaft (average pain scores of 9, 8.7, and 7.3, respectively) (see Table 1). The 3 least painful locations were the skull, middle toe tip, and upper arm, all scoring a 2.3. Why were certain locations more or less painful? For the most painful locations, sting depth may be important, because the skin is thinnest on the genitals, followed by the face (Ya-Xian et al 199925ya). The nose and lips are orifices, so they may also have lower pain thresholds for protection. Stings to the nostril were especially violent, immediately inducing sneezing, tears and a copious flow of mucus. The sting did autotomize in the nostril (self-severed when the bee was pulled away). The copious mucus flow, however, may help prevent subsequent stings to the area during a natural attack.
…It is plausible that a ‘pain’ homunculus would look different from a somatosensory homunculus.