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BYB Summer Camp Presents: Scorpions?! Why’d it have to be scorpions!? – A Screenplay by Dylan the Scorpion King

A pitiable foo

A scorpion by any other name

Greetings!  My name’s Dylan, and I’m interning at a company that loves cockroaches here in the land of the Wolverines, where I’m proud to represent Michigan State University’s burgeoning undergraduate neuroscience program. My project involves an examination of scorpion neuroscience, particularly the electrophysiology of their nervous system, and I’m working in collaboration with the Venom Evolution lab of Ashlee and Matthew Rowe at MSU (  Little is known about scorpions compared to other kinds of organisms, and even less is known about their nervous system. I’m hoping to shed some light on the shocking mysteries which still lay beneath the armor of these arachnids.

**quick local note**

If you want to learn more about scorpion biology, I’ll be doing a public talk about some of the unique aspects of scorpion biology next Tuesday, July 1st, at 7 pm at All Hands Active.  There will be live scorpions (in boxes, don’t worry) so bring your questions for them! Example question: “Mr. Scorpion, what is it like to be the most awesome of all arachnids?”

**quick global note**

Also, all of the youtube videos linked in this post are from my channel where I will occasionally post my experimental and amateur home videos of the scorpions, whom I now live with (not the best roommate choice, but beggars can’t be choosers when it comes to subletting. At least they don’t leave dirty dishes out.)



Who wouldn’t want to live with and do research on this?


Many of a scorpion’s most important sensory systems for survival are located on their legs. A scorpions’ legs are extremely sensitive to any form of touch or vibration, what we call mechanosensation. The legs are so sensitive to mechanical stimuli that they can even sense with a high degree of accuracy what direction and how far away something is just based on the ground vibrations it puts out. This mode of sensing prey was first described through the work of Dr. Phillip Brownell in the 70’s (as an example: Brownell PH (1977) Compressional and surface waves in sand: used by desert scorpions to locate prey.Science 197:479-482, Bronwell & Farley 1979a, b, and c) where it was demonstrated that scorpions whose eyes were covered are still able to orient themselves towards vibrations with a very high degree of accuracy.  In effect, the scorpions “see” with their legs, and don’t require their other senses in order to locate prey.



This scorpion can feel that the fuzzy pink teddy bear is friend, not food


This behavior is mediated by a small organ, built into the scorpions’ exoskeleton, located near the end of their legs called the Basitarsal Compound Slit Sensillum (BCSS).  With two of the scorpions involved in my experiments, I have been able to replicate this behavior by gently tapping the ground with tongs.

Orientation behavior in an asian forest scorpion


Attack by an emperor scorpion that apparently doesn’t like salad


The initial goal was to use the pre-existing Roboroach system, which applies light electrical stimulation through implanted electrodes, to induce this orientation behavior in a scorpion when no vibrations were present.  Unfortunately, the sensory organ itself is fickle in activation and prone to failure if damaged.  In an attempt to access the neurons that take this signal from the end of the leg, where the scorpion senses vibrations, to the brain where it activates the behavior, an electrode was implanted partway up the scorpions’ leg, on the same segment as the BCSS.


A stunningly lifelike drawing of a scorpion leg from my lab notebook, showing the implant location


While this initial stimulation failed to elicit the predatory reorientation behavior as hoped, it serendipitously managed to evoke another, dramatic display of scorpion behavior: a defensive response.  In the initial attempt at stimulating two legs simultaneously in this new surgery location, the scorpion would reliably sting between those legs once stimulation reached a certain threshold.  In this setup, however, I was applying continuous stimulation, so it was hard to tell if I was evoking a specific response to stimuli or if the scorpion was just getting annoyed, so further exploration was required.

An example of this response from the aforementioned stimulation

The next tests required applying short, controlled bursts of stimulation to ensure that it was direct electrical stimulation of certain neurons which evoked this response and that it could be reliably brought about through stimulation. As it happens, when receiving bursts that exceeded a certain voltage, frequency, and duration, the scorpion would reliably sting at the same location, at a target organism which didn’t exist.



This shows, from my lab notebook, two examples of the degree of electrical stimulation which induced a stinging response.  And yes, I’m aware I have horrific handwriting.

Two videos showing the induction of this response.

Brief pulses of low electrical stimulation therefore appear capable of evoking this behavior-but what behavior is it, and why?  There is a paper (this time from the 60’s!) that examines a behavior very similar to what we appear to be inducing – “Toward the Physiological Analysis of Defensive Responses of Scorpions” (Palka & Babu, 1967).  In it, they elicited very similar behavior from scorpions through light mechanical stimulation applied to the surface of the legs.  They referred to this as the “defensive strike”, and called it “defensive” (as if defending from an attacker) based on the nature of the stimulus applied and on comparison between this behavior and how differently scorpions behave in response to prey.  If you’re wondering what on earth would ever prey upon a scorpion, the answer is often other scorpions-and on occasion, mammals such as mice (see the work of Ashlee and Matthew Rowe).

One observation in the paper that bears examination in our setup was that the closer to the scorpions’ tail the stimulated leg is, the more likely it is the scorpion will respond with the sting alone, with the reverse applying to response with the claws. All the tests thus far have involved stimulation to the rear set of legs, so future investigation will be done to see if a claw response can be evoked through stimulation of the legs closer to the front.

Scorpion kankles

Anesthetized scorpion, held down with molding clay, showing wire electrodes implanted in rear two right-side legs, with ground implanted into the abdomen.


However, before drawing overly broad connections between our results and this behavior, one more test was required – I needed to make sure the Roboroach backpack was capable of eliciting it. This would allow me to better demonstrate that it was stimulation from the implanted wires which caused this behavior, and that the behavior could be evoked on either side of the scorpion.

This video shows the results of that experiment (my apologies for the brief language, consider this video PG-13, I was caught off guard by the intensity of the scorpions’ response – you may want to mute it for the first 8 seconds).

(also, scorpions glow under UV light! They are naturally fluorescent – so if you’re every trying to find a runaway scorp, break out the blacklight!)

So!  There is a lot of future work that needs to be done.  I need to further quantify the result of inducing this sting response on either side of the scorpion.  I also need to figure out a more secure way to affix these electrodes and the Roboroach backpack – the procedures and tools for implanting them were made for a cockroach about ? the size of this scorpion and a smaller fraction of its strength.  I would also like to examine exactly which neurons are being stimulated – Palka and Babu were unable to identify the receptors responsible for evoking this response, so perhaps that’s a question this setup can answer.  I’m also still interested in exploring the prey-seeking orientation in the scorpions, and have a few surgical procedures to try that may get me closer to evoking that through stimulation as well.

You may ask, where is this all heading, or what is the ultimate goal of my research?  For that, I will leave you with this photo of my intended end-game.



Hail to the King, baby.


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