The Sting of the Honeybee

Worker bee, taking a break.

Internal lateral view, showing the seventh segment which hides segments 8 and 9 which form the sting.

Internal lateral view, showing the seventh segment which hides segments 8 and 9 which form the sting.

A worker bee, when threatened or when protecting the hive, may sting. All worker bees are females, and all have a stinger at the end of the abdomen. This stinger is a modified ovipositor (egg-laying organ), which has evolved to become a defense tool. Usually, workers will not lay eggs because ovary production is suppressed by pheromones released by the brood. However, if the queen dies or swarms, some of the remaining workers may develop ovaries, and the eggs, once laid, can develop into drones.[1]

 

blb - bulb of stylet Lct - lancet Ob - oblong plate Qd - quadrate plate Sh - sheath lobe Stl - stylet Tri - triangular plate

blb – bulb of stylet, Lct – lancet, Ob – oblong plate, Qd – quadrate plate, Sh – sheath lobe, Stl – stylet, Tri – triangular plate

A bee stinger

A bee stinger in human skin

The stinger (or lancet) is barbed, which serves to help penetrate the surface,  but also prevents easy withdrawal. Although the sting is usually left behind after stinging a person, that is not always the case in other victims because it depends on the texture of what it is being penetrated.  Queen bees do not leave the stinger behind because the barbs are smaller.

The mechanical action of stinging as described by David Cushman follows below (Credit: Dave Cushman’s website, generously provided copyright-free)

“When the sting is deployed, the bee bends it’s abdomen downward due to the actions of the muscles that connect the abdominal plates. The muscle set on the ventral side contracts thereby increasing the overlap between the sternite plates. On the dorsal side another set of muscles contract so that the membrane between the tergite plates is distended. This results in a bent abdomen, which in combination of the angular ventral movement of the sting shaft (in turn caused by the furcula muscle). This ensures that the sting shaft enters roughly perpendicularly into skin of the victim. Perpendicular penetration is the most efficient as venom is delivered more deeply and the path through the tough skin is shortest. The force from the bee’s legs, the muscles of the abdomen and the effect of the backward raked barbs, as the lancets reciprocate alternately, all combine to produce a thrust that drives the penetration of the sting.”

 

Animation of sting of honey bee worker.

Animation of sting of honey bee worker. After Snodgrass (1910, fig. 36)  and (1956, fig. 62FG)(scale bar = 0.5 mm)

“Venom is pumped into the central canal by the reciprocating action of the lancets, each of which has an umbrella like collector and valve (within the liquid contained in the bulb) The pulses of venom are delivered through the canal and squeeze out between the rubbing faces of the two lancets.”

Flattened image of the sting mechanism by David Cushman.

Flattened image of the sting mechanism by David Cushman.

 

bee-stinger-animation

Animation of venom delivery in a bee stinger. Image use according to www.StatedClearly.com guidelines

“This is another feature that is of high efficiency as the venom comes into contact with a much larger area of tissue than would be the case if the sting were similar to a hypodermic needle. The venom also leaks to a small extent from the exposed portion of the sting shaft providing a pheromone alert at the earliest possible moment.”

 

Sting tip of honey bee worker seen from below. Two stylets of the sting can move along the lancet. When barbs of one stylet prevent the sting from going out, the other stylet gets deeper into the victims body. (scale bar = 0.1 mm) The two rows of barbs are distributed along curved lines, therefore, the sting rotates clockwise about 8 degrees during penetration of victim's skin [1].

Sting tip of honey bee worker seen from below. Two stylets of the sting can move along the lancet. When barbs of one stylet prevent the sting from going out, the other stylet gets deeper into the victim’s body. (scale bar = 0.1 mm) The two rows of barbs are distributed along curved lines, therefore, the sting rotates clockwise about 8 degrees during penetration of victim’s skin [2].

Most people who have an interest in macro photography or domesticated honeybees have probably come across Kathy Keatley Garvey’s image of a bee sting. In that image you can graphically see the long and ‘drawn out’ death of a bee: as she attempts to fly away, her stinger remains embedded in the skin of the victim, anchoring and eventually tearing out some internal organs from the bee’s abdomen as it attempts to fly away.

Beekeepers shrug off bee stings. During our -1½ hour-long session there were only two stings, one under a fingernail when a frame was being removed, and another (triggered deliberately for educational purposes) on the back of a beekeeper’s hand. This is what happened:

It is obvious from the above image (thanks to one tough self-volunteered apiarist!) that a worker bee will not long survive after stinging. The sting structure, venom sacs, musculature, nerves and even part of the digestive tract are all torn out when the bee flies off or is removed. To those not used to being stung by bees, or who are allergic to bee stings (carry your EpiPen!) the pain may seem a harsh warning, but for the bee it means certain death.

(Unless otherwise credited, all line drawings are copyright Adam Tofilski, and are used in concordance with his terms.)

References

1. Page R.E., Erickson E.H. (1988) Reproduction by worker honeybees (Apis mellifera L). Behav Ecol Sociobiol 23:117-126.

2. Wu J., Yan S., Zhao J., Ye Y. (2014) Barbs Facilitate the Helical Penetration of Honeybee (Apis mellifera ligustica) Stingers. PloS one 9:e103823.

The structure of a Honeybee sting by David Cushman

Honeybee by Adam Tofilski

Wikipedia

Zhao, Zi-Long et al. “Structures, Properties, and Functions of the Stings of Honey Bees and Paper Wasps: A Comparative Study.” Biology Open 4.7 (2015): 921–928. PMC. Web. 15 May 2016.

 

This entry was posted in Alberta, Apidae, Behaviour, Canada, Edmonton, Education, Hymenoptera, Insect, macro, photography, Season, Spring, Workshop and tagged , , , , , .

5 Comments

  1. Gary Anweiler 15 May, 2016 at 12:48 PM #

    Very nice..and VERY cool!!

  2. Andrea Jackson 15 May, 2016 at 10:44 PM #

    A most interesting post, Adrian! As if tempting fate, I have only been stung by a bee once, on the bottom of my foot, as a child. A teabag on it was my Nana’s solution. Since I have been working closely with bees taking their photos, I have a new respect for their tolerance of this bumbling human.

    • Adrian 19 May, 2016 at 10:01 AM #

      Same here, my one and only sting came when I was a kid, when a bee rested on my leg, inside my rubber boot. I can’t blame her for stinging!

  3. Annie Pang 16 May, 2016 at 12:21 AM #

    Wow again Adrian! I knew that Honey Bees died after stinging, but have never known the graphic details (which I do now!). Very well done! I have never been stung by a Honey Bee, but have been by Yellow Jackets. Once I put my hand inside a gardening glove left out on the back porch, not realizing that a wasp had made it a nice napping place. Ouch!!
    A very well put together piece. Love the photo of the Honey Bee’s face! Great eyes! 🙂

    • Adrian 19 May, 2016 at 10:02 AM #

      Thanks Annie! Mostly I just conglomerated existing web material, but my photos of the sting taking place was an eye-opener for me too!

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