Effects of colored light on Vanessa Cardui Caterpillars For my team s experiment, we are studying the painted lady butterfly. Its scientific name is Vanessa Cardui. We are studying them in their juvenile stage or before pupation- when they are caterpillars. They inhabit open, brightly lit environments. Usually it takes two weeks or more to begin pupation. An adult painted lady will emerge from the chrysalis after seven to ten days in the pupa. It emerges quickly from its chrysalis. It takes a minute or less for it to fully emerge. After coming out of its chrysalis, it takes three to four hours for the new adult butterfly to be ready to fly. The painted lady then dies after three weeks. We are performing our test on commercially bought larvae. These are important because we need to know how to simulate the butterfly s environment, and be sure the caterpillars are rowing properly. We are studying if the color of light affects the growth of the caterpillar. Our question is: Do caterpillars grow faster in red colored light, or in normal light? We decided to study this problem to see if red light increases the rate of growth in painted lady butterflies. If the growth rate is faster with the red light, caterpillar- selling companies can produce larvae more quickly. We know that the Vanessa Cardui, lives in open, brightly lit environments. So we want to find out whether or not red light quickens the growth rate of painted lady butterfly larvae. Our hypothesis is that the red light would cause the caterpillars to grow slower than the normal light. We predicted that the red colored light s wavelength (which is long) and frequency (which is low) would cause the caterpillar s growth rate to slow down. We tested this with two of the same lamps, using one fluorescent light bulb for each lamp. The only difference is that one light bulb isn t colored and the other is red. We tested it in a dark environment, and each day measured the temperature and documented each caterpillar s growth, or if they died. Each caterpillar was in its own plastic container with 7.5 grams of food each.
Materials. 30 Small plastic cups with lid: Used to house the caterpillar and food under it. Caterpillar Food: Used to feed caterpillars (7.5 grams per caterpillar) 3. Lamps: Used to Provide light for the experiment 4. Fluorescent Light bulb: Used for e control group s normal colored light 5. Red Fluorescent Light bulb: Used for the treatment group s red light 6. Thermometers: To measure the temperature of both enclosures 7. Paintbrush: to check if the caterpillars are alive or not throughout the experiment 8. Bins/Containers: To separate and keep the Treatment and Control Groups (no lid) 9. 30 Painted lady Caterpillars: To perform the experiment on 0. Scale: to measure amount of food for caterpillar (7.5 grams per cup). Kabob Sticks: Holds up pupas ( pair for each pupa) ITEM Small Plastic Cups: Caterpillar Food: Lamps: Fluorescent Light Bulbs: Red Fluorescent Light Bulbs: Thermometers: Paint Brushes: Bins/Containers: Painted Lady Caterpillars: Scale: Kabob Sticks: NEEDED 30 7.5 grams per cup 30 per pupa Methods- We conducted a T test with the Data, to see if there was a large enough difference to reject the null. We also found the Variance to perform the T test, and found the mean (or average) of the Data.
Results Quantitative Results: Days Until Pupation: Control Group (Normal Colored Light) Treatment Group (Red Light) C- dead T- Dead C- days T- Dead C3- Dead T3- days C4- Dead T4- Dead C5- Dead T5- Dead C6- Dead T6- Dead C7- Dead T7- Dead C8- days T8-0 days C9- Dead T9- Dead C0- days T0- Dead C- dead T- Dead C- dead T- days C3- dead T3- dead C4- dead T4- dead C5- dead T5- dead Results: After analyzing our data, using a T- test to find our results- we were quite surprised. The Color of the light, unlike what we had thought- did not affect the caterpillars growth rate. We found that there was not a sufficient difference between the data from the control and treatment groups. Or that the result of the T- tests, or p value, was more than 0.05. (Look Figure ) (Figure ) In result, we failed reject the null hypothesis.
Conclusion We found that different colored light does not affect the growth of the Vanessa cardui, or Painted Lady Butterfly larvae. I think we got our results because the butterfly s natural habitat is a well- lit environment, and that the color of the light does not affect its growth. I am surprised that due to the results, we failed to reject the null. I think a possible error was that every day that we checked the caterpillar s growth; we had to move the bins around each other. That could have moved the caterpillars around and injured them. I think the potential source of the error, moving the bins around too much and possibly injuring the caterpillars, was caused by limited space for checking the caterpillars. This error may not have happened if we had more space to spread out the caterpillars evenly, making the caterpillars easier to check without moving them around. Due to internet searches and speaking to professors, this is seemingly the first time this test has been conducted. Seeing we have nothing to base it on, we don t know if these results agree with other conclusions. Next, I would like to test if different amounts of light would affect caterpillar s growth. I think this would be interesting to study because since the butterflies live in well- lit environments, maybe they might grow slower in the dark or not at all. Now that we know that colored light does not affect its growth, it would be cool to find out if different amounts of light would.
Bibliography 03 The Regents of the University of California, Lawrence Hall of Science: 7/6/3 http://lhsfoss.org/fossweb/teachers/materials/plantanimal/ladybutterfly.html