Adaptations of Terrestrial Isopods to Varying Wavelengths of Light
Danielson, Sharon Jean
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The problem. The purpose of this investigation was to determine the response of terrestrial isopods that were subjected to prolonged periods of varying wavelengths of light, and to measure this adaptability by locomotor activity. Procedure. Terrestrial isopods were randomly collected from their natural environments, placed in study chambers, and subjected to red, blue, green, white, and no light for three days. The isopods were then removed from the study chambers and placed on culture plates containing nutrient agar. The culture plates were exposed to a white beam of light in the center of the plate for five minutes. The distance traveled by each light-adapted sowbug in response to the white light was then measured. Findings. Terrestrial isopods adapted to the red and blue wavelengths prior to exposure to the white light, showed statistically significant movement when placed on the culture plates. Isopods subjected to the green and white wavelengths, and to the dark, showed less statistically significant movement. The control isopods, those not exposed to the beam of white light, showed more locomotor activity than did the experimental isopods. Conclusions. Terrestrial isopod behavior appears to be controlled by the environmental conditions of temperature and humidity and not so much by light and dark as previously reported. The isopods adapted to the red and blue wavelengths showed more significant locomotor activity. This is agitation due to the red and blue wavelengths as shown in other crustaceans. With the other isopods, results were very similar as long as the environmental conditions of temperature and humidity remained constant. Recommendations. Additional studies of terrestrial isopods need to be conducted to determine the importance of temperature, humidity, and photo-negativity. Other research needs to be carried out to further examine the effects of blue and red wavelengths on terrestrial isopods and other crustaceans.
30 leaves. Advisor: Dr. Rodney Rogers