The Effect of Temperature on the Respiration Rate of Tenebrio molitor


Kelly Bays


University of Colorado, Boulder - Fall 2006


         I tested the affects of cold and hot temperature on the respiration rate of Tenebrio molitor (also known as mealworms).  Mealworms are cold blooded and this fact should relate to how their respiration rate is affected by temperature.  A basic rule of biochemistry is cold temperatures slow down reaction rates, while hot temperatures increase reaction rates.  If cold blooded animals follow this rule of biochemistry, then in cold temperature, the wormsÕ respiration rate (corresponding to the carbon dioxide concentration) will decrease and in hot temperature, the wormsÕ respiration rate will increase.  Cold blooded organisms will follow the basic rules of biochemistry; cold temperature slows respirationÕs reaction and hot temperature increases respirationÕs reaction.

         My experiment included three groups of five worms in a gas chamber.  I also used one container of snow, one container of hot water, and a carbon dioxide probe.  I maintained the temperature of the snow, which was zero degrees Celsius and the hot water, which was 42 degrees Celsius through the entire experiment.  I also found the mass of each group of worms.  To begin my experiment, I put five mealworms into a gas chamber and let the chamber air out for five minutes and waving my hand over it to increase airflow. Then, I connected the carbon dioxide probe to the gas chamber and placed the chamber into the snow.  I waited a minute to let the temperature inside of the chamber change and then I began my calculations on the computerÕs graph for five minutes.  I recorded the slope for my results.  Then, I took the chamber out of the snow and the probe out of the chamber.  I allowed the chamber to air out again for five minutes to bring wormÕs air temperature and respiration rate back to normal.  I then put the probe back into the chamber and stuck the chamber into the hot water.  I repeated the same procedure, but with hot water.  I repeated the cold and hot temperature steps two additional times with two different groups of five worms each.  I predicted that the wormsÕ respiration rate (and carbon dioxide rate) to increase again in hot temperature and decrease again in cold temperature since that was the case for the first group of worms.

         My results showed that the wormsÕ carbon dioxide rate and respiration rate were significantly lower in cold temperature (with a mean of 0.62 ppm/sec/g) as compared to the wormsÕ carbon dioxide rate and respiration rate in hot temperature (2.1 ppm/sex/g). My results also showed to be consistent proven by the two-tail P number; 0.007. This number was less than 0.05 which shows the results to be consistent.

         I fail to reject my hypothesis because my results showed that cold temperature decreased the wormsÕ rate of respiration, while hot temperature increased the wormsÕ rate of respiration.  These results show that wormsÕ cold blooded nature have a direct relation to the biochemistry rule of reactions increasing as the temperature increases. Each of my calculations (found by the slope of the carbon dioxide rate, divided by the mass of the worms) in cold temperature were very similar.  This is also true with my calculations using hot temperature.  Though, problems that may have occurred during my experiment are; a worm having a respiration problem, the carbon dioxide sensor not working correctly, and/or calculation mistakes.  Other studies seemed to by consistent with my study.  In 2005, the study ŌThe Effect of Temperature on the Respiration Rate of Acheta domesticasĶ by Andrew Laszlo, Amy Long, and Erin Hauver show that cricketÕs respiration rate also decline as the temperature declines.  Though, this experiment was slightly different because it increased the temperature from 5 degrees Celsius to 40 degrees Celsius in 5 degree increments every three minutes.  Also, crickets may have a higher respiration rate than worms which may have affected results. Yet, the results were consistent with by results with mealworms.  Perhaps another experiment may be done with warm blooded animals to determine how temperature affects these warm blooded organisms.  The new experiment may be set up similar to my worm experiment.   This test would be interesting to compare to experiment; perhaps the warm blooded organisms will have results inversely proportional to the cold blooded organisms.