Do Crickets Ever Get the Blues?

 

Sam Percy

 

CU-Bouder, Fall 2006

 

         As the sun’s golden fire fades into depthless darkness in the summertime there is one noise that everyone expects to hear, the “chirping” of crickets. Crickets create this “chirping” noise by rubbing the ribbed end of one of their wings against the smooth end of the other.  Crickets use “Chirps” as alarm signals, to initiate courtship, and to intimidate potential foes. In order for a cricket to receive these signals it must have some way of “hearing” the different chirps. A cricket has its own version of an eardrum just below its “knee” on its front leg.  We hypothesized that since different types of music create different pitches and different types of sound and different types of sounds or “chirps” cause crickets to react differently, there must be some correlation between the ways a cricket reacts and the type of sound a cricket hears. We interpreted the way a cricket reacts as the change in its respiration rate.

         We decided to test our hypothesis by placing a cricket in a closed chamber and measuring the change in carbon dioxide concentration while different types of music were being played inside the chamber. The change in carbon dioxide concentration would be the same as the change in the cricket’s respiration rate since the cricket is the only thing producing carbon dioxide in the chamber.  We used three different types of music and played them for three minutes each.  The first type of music was complete silence and was used as the experimental control simulating a cricket at its “natural” respiration rate. The second type of music was Aaron Copeland’s classical song, “Appalachian Spring.” The third type of music was Ozomatli’s jazzy, hip-hop, funky hit, “Saturday Night.” The songs progressed from no noise to very smooth, calm, and flowing to extremely lively, exciting, and groovy. We predicted that as the intensity and excitement of the music increased from no noise to classical to funk the crickets’ respiration rate would increase because they would interpret the noises as danger and become stressed out.

         We ran trials with 5 different crickets to try to gain as broad a range of data as we possibly could. The means for all five crickets’ respiration rates were for no noise, 83.4ppm/min/g, for classical 43.6ppm/min/g, and for the funk 34.8ppm/min./g. Though the means suggest there is a trend the ANOVA test we ran on the data yielded a p-value of .196, well above the required .05 for the data to be significantly different. This meant that none of the means were significantly different from each other. This probably resulted in the large variance in our data ranges between crickets.

         Our results forced us to reject our hypothesis. We predicted a significant difference between the three types of music with the respiration rates increasing as the music got more exciting. Our results suggested there was no significant difference between the three types of music and that the respiration rate if anything actually decreased as the excitement of the music increased. Our results seemed to be consistent with those from the “Cable” website. Some groups had placed heat upon crickets and measured respiration rates. They also had noticed a decrease in respiration rate as the temperature or “stress” of the cricket increased.

Some potential sources of error in our experiment could be the fact that we didn’t differentiate between males and females and the short run times of our trials. We found out during research after the experiment that female crickets cannot hear and females were present in the container we took our crickets from so our data could have been swayed by crickets who couldn’t actually hear the music being played. Our run-time was also only 3 minutes and this might have been a little short to obtain an accurate respiration rate for the crickets causing the reported rates to be inaccurate.

To follow up this experiment I would probably try a similar experiment, but this time use all male crickets because they are the only ones that can hear and choose songs that are 5 minutes or longer to play for the crickets. I also would want to try to make the music louder inside the cricket’s chamber by using some sort of small speaker system that could fit inside the chamber. However, based upon the data we obtained it seems there will never be any great cricket musicians because they don’t get excited when the music starts rocking.

 

 

Hart, Stephen. “Crickets.” November 6 2006. http://acp.eugraph.com/insects/crickets.html

 

“Insecta Inspecta World.” November 6 2006. http://www.insecta-inspecta.com/crickets/field/index.html

 

Poulet, James. “Cricket Hearing and Steering.” November 6 2006.

http://acp.eugraph.com/news/news04/poulet.html