The Effect of Vibrational Frequency on the Mojave Dune Scorpion, Smeringus mesaensis
Jodie Tarpo, Kacey Kilpatrick
Department of Biological Sciences
SaddlebackCollege
Mission Viejo, California92679
The Mojave dune scorpion, [insert] Scientific name, perhaps the best studied scorpion, why is it the best studied? List previous studies is known to detect vibrational frequency through sand substrate [insert] in order to hunt prey and sense changes in its immediate environment. (Reference?) Previous studies have shown a clear positive relationship between amplitude and neural response,as might be expected. (Reference) To determine a possible relationship between specific frequency and neural response, six dune scorpions were submitted (or exposed to)to various frequencies. [inert] State the hypothesis.Due to the extremely faint signal of the action potential, data was insufficient[insert] (p value), and no clear determination could be(was) made.
Introduction
With very limited visual senses, scorpions rely heavily on other stimuli in order to detect and respond to vibrational frequency intheir immediate surroundings. Their main senses consist of chemoreception as well as light and vibrational detection (Brownell-Farley, 1978; Gaffin-Knowlton, 2009). In many arachnids, there is seismic sensitivity in the basitarsal-tarsal joints affected by amplitude (Brownell-Farley, 1978; Falgiani, 1999). Their ability to detect vibrational stimuli is invaluable to their ability to detect prey, but in some arachnids it has even been shown to be a form of communication, through drumming (Henschel, 2002). They also have eight specific orientation detectors, similar to visual orientation in mammals. This has been shown behaviorally and through computational theory (Brownell and Farley, 1979b; Brownell-Hemmen, 2001). Each of the eight orientations of sensitivity has been tested and accounts for a change in the ability to detect motion from (their potential)prey (Brownell-Hemmen, 2001). The basitarsal-tarsal slit sensilla in sand scorpions have been shown to detect frequencies at various amplitudes (Brownell-Farley, 1979). The anatomy of the trichobothria on their walking legs has been outlined thoroughly (Messlinger, 1987), but they themselves remain to be fully investigated as sensitive detectors of vibrational motion at various frequencies. State hypothesis.Pertinent data would give better insight into the mechanisms by which these creatures hunt prey, and could potentially be utilized in detectional bio-equipment.
Materials and Methods
Ten scorpions were purchased at nine dollars each from LLLReptiles (Oceanside, CA; San Diego, CA). They were kept in separate eight-by-eleven inch plastic containers to prevent cannibalistic behaviors (Farley, Polis, 1979; Polis, 1980). Holes were drilled into the lids to allow for respiration. The containers were filled with two inches of sand for the specimens to burrow;
(new sentence). Ssmall crickets were fed to the scorpions once every weekfor how many weeks?. Natural lighting was utilized.
Before performing the experiment, each of the largest six scorpions why the 6 largest?? Does size matter when measuring the effect amplitude has on basitarsal joints?was chilled in a freezer at 4ºC for four minutes in order to stabilize the specimens and slow down their activity; this did not pose danger to the organism (Baust- Gonzalez-Whitmore, 1985). Were the scorpions were tested at this temperature? Utilizing forceps with gloved hands, a scorpion was picked up gently and placed onto a translucent CDFirst time using CD—write our what it stands for, followed by (CD)under a stereo microscope. Wax was then used to bind the specimen’s tail and pedipalps to the CD for stability while performing the test. In addition to the utilization of wax, double-sided tape was also used to keep the 4th right leg still against CD, stabilizing the test site. The 4th right leg was chosen to test because of its large size, ensuring greater accuracy of measurement. Using a frequency generator, various wavelengthsof frequency were emitted through a speaker, placed 25cm away from the specimen. An oscilloscope was connected to both the frequency generator and a platinum wire probe inserted into the BCSS(BCSS? Again—first time using it. What does it stand for?) of the 4th right leg of the scorpion, allowing for comparative visualization. After each scorpion was fixed with the probe inserted, the frequency generator was initialized, the signal relayed at constant amplitude and at an initial frequency of 20 Hz. We continued this process in upward steps of 100 Hz. Passed through a music amplifier, the signal was relayed into a laptop and recorded with Audacity. Do any of the references state at which frequency the scorpions respond?
Each spike per time interval would be counted as an action potential; henceallowing to determine the frequency at which the action potentials hit(for lack of a better word).frequency of potentials could be determined. Each of the 6specimen would be recorded with and without the stimuli for control.
Results
Neither the control test nor the experimental test yielded any response. The mean number of spikes (which was zero), (average mean= 0)for all specimens was calculated, examined, and compared to frequency, as shown below.
Figure 1. The mean number of spikes per interval (100 Hz) of frequency (n=6, p=incalculable).
Figure 2 (left). Setup of experiment. Laptop, music amplifier, frequency generator, oscilloscope, speaker, and stereomicroscope (from left to right).
Figure 3 (right). Close-up view of stereomicroscope.
Nice pictures, but figures 2 and 3 do not help with supporting data.
Discussion
The lack of clear spikes in amplitude, indicating action potentials in the neurons of the scorpions, can be attributed to several possible errors. Include numeral data.., pvalue, mean, even though undermined. As the scorpion continued to move and eat when fed, it is unlikely that it had died or remained in a vegetative state. However, it is entirely possible that the noise to signal ratio was too high, so that a simple parsing of information was not possible (Kim-Kim, 2000).
Was the sand deep enough (to their tarsal joint)for the scorpions to feel the vibrations?
Perhaps for further experimentation.. tie up all six joints, not just one
Further attempts at this study wouldmayrequire a differential amplifier to get a high signal to noise ratio. Other possible cause for error could be a misplacing of the microelectrode, or an insufficient sharpness therein. However, even a misplaced probe would display some kind of signal due to a cell potential, so the greatest likely error was the noise to signal ratio.
References
Baust, J.G., Gonzalez, R., and Whitmore, D.H. (1985). Scorpion Cold Hardiness. Physiological Zoology, 58 (5), 526-537
Brownell, Philip & Farley, Roger D. (1978). Orientation to vibrations in sand by the nocturnal scorpion Paruroctonus mesaensis: Mechanism of target localization. Journal of Comparative Physiology A, 131(1), 31-38.
Brownell, P.H. & van Hemmen, L.J. (2001). Vibration sensitivity and a computational theory for prey–localizing behavior in sand scorpions. Oxford Journals, 41(5), 1229-1240. Sept. 13, 2001
Falgiani, Michael (1999). Electrophysiological investigation of the sensitivity of scorpion basitarsal compound slit sensilla to vibratory stimuli.
Henschel, J.R. (2002). Long-Distance Wandering and Mating by the Dancing White Lady Spider (Leucorchestris arenicola) (Araneae, Sparassidae) Across Namib Dunes. The Journal of Arachnology, 30(2):321-330.
Kim, K., & Kim, S. (2000). Neural Spike Sorting Under Nearly O-dB Signal-to-Noise Ratio Using Nonlinear Energy Operator and Artificial Neural-Network Classifier.IEEE Transactions On Biomedical Engineering,47(10), 1406.
Knowlton, Elizabeth D. & Gaffin, Douglas D. (2009). A new approach to examining scorpion peg sensilla: the mineral oil flood technique. TheJournal of Arachnology.
Messlinger, Karl (1987). Fine structure of scorpion trichobothria (Arachnida, Scorpiones). Zoomorphology, 107(1), 49-57.
Polis, G.A. (1980). The effect of cannibalism on the demography and activity of a natural population of desert scorpions.Behavioral Ecology and Sociobiology 7: 25–35.
Polis, G.A. and Farley, R.D. (1979). Behavior and ecology of mating in the cannibalistic scorpion , Paruroctonus mesaensis Stahnke (Seorpionida : Vaejovidae). J. Arachnol. 7 :33-46.
Review Form
Department of Biological Sciences
SaddlebackCollege, Mission Viejo, CA92692
Author (s):____Jodie Tarpo and Kacey Kilpatrick______
Title:__The Effect of Vibrational Frequency on the Mojave Dune Scorpion, Smeringus mesaensis_
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
Past experiments show that scorpions lack visual senses, thus relying on nearby vibrations in order to capture its prey, and even to communicate. Researchers conducted an experiment to determine if there is a direct relationship between frequency and neural response in scorpions. A probe was inserted in the scorpions’ basitarsal-taral joints, which are affected by amplitude. Then, scorpions were exposed to different frequencies through a speaker at 100 Hz intervals. Action potentials were recorded from a program called Audacity. Each spike, indicating an action potential, was counted in order to determine the frequency of potentials. The results yield no response, for both the control and experimental group, to the frequencies on which the scorpions were exposed to.
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our current state of knowledge.
I understand what they were testing, but not being clear on the hypothesis being tested on is a major weakness in this paper. Abstract is weak, needs more information on results, and needs to state their hypothesis. Abbreviations in methods section needs to be written out once so I know what it is short for. Some unnecessary figures in results section. On another note, the paper was well organized, citations were correctly written, and methods were appropriate. It’s a shame no results could be determined, it would be interesting to see at what frequency they run away as a predator, and at what frequencies they run to its prey.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical errors, and minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the manuscript.
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Refer to my corrections indicated in red.
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