Behavioural responses of Periplaneta americana to red, blue, green and white light colours Lindsay...
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Transcript of Behavioural responses of Periplaneta americana to red, blue, green and white light colours Lindsay...
Behavioural responses of Periplaneta americana to red,
blue, green and white light colours
Lindsay Grant, Ashley Mah and Gillian TetlowBIOL 3401
Mount Allison University
The American Cockroach
• Not endemic to America
• Natural habitat:• Mainly found in dark, damp areas • In populated areas they often live in basements
• Have very quick reflexes
The Compound Eye
• Sensitive to light levels and specific colours
• Composed of:• Ommatidia • An optical system • Photoreceptor cells
• Within the optical system there are variants for nocturnal animals• Superimposed eyes or apposition eyes
Sensitive to Wavelengths
• Walther (1958)• Examined the spectral sensitivity and the action potential of the compound
eye • The peak sensitivity curve occurred in ultraviolet lights• Results showed the compound eye has the ability to discriminate colours
Goal of Study
• Determine if movement is influenced by different light colors • Observe general behaviours:• Was the cockroach sprinting around the tank or calmly moving?• Was there centre line avoidance under certain light colors?
Hypothesis
• Cockroaches will show the greatest movement and no centre line avoidance in blue and green lighting.
Methods
• Experimental environment: dark, warm room
• Experiment conducted in a small rectangular fish tank
• Transect lines drawn 3x6 with a 2 cm starting space
• A 40watt spotlight placed above the tank
• Light conditions: normal white, blue, green, and red
Collecting Data
• 5 trials for each condition
• 2 minute acclimation then moved to starting space
• Observation period of 3 minutes to count peripheral and centre line crossing
Peripheral and Centre Lines
Peripheral boxesCenter boxesStart Area
Results
• Peripheral line crossing:• Highest - Green light, 75 lines• Lowest - Red light, 41.4 lines
• Centre line crossing• Highest - Green light, 4.8 lines• Lowest - Normal white light, 2.4 lines
Figure 1. Mean (±SE) number of peripheral line crossings of cockroaches (Periplaneta americana) in four light conditions (n=5): blue, red, green, and normal white. Lines were drawn 6x3 (L x W) in a boarded rectangular fish tank and observations occurred for 3 minutes following a 2-minute acclimation period.
Figure 2. Mean (±SE) number of centre line crossings of cockroaches (Periplaneta americana) in four light conditions (n=5): blue, red, green, and normal white. Lines were drawn 6x3 (L x W) in a boarded rectangular fish tank and observations occurred for 3 minutes following a 2-minute acclimation period. The centre lines
consisted of the middle row.
Blue and Green Light
• Perceive colour in the blue-green range of the visible light spectrum
Walther 1958• True colour vision• Blue green light is the same as dark stimulation
• More line crosses
Harker 1955
• Circadian rhythms
Wiedenmann 1977
Koehler et al. 1987
• red light appears the same as dark light
• gold and red light cause less activity in German cockroaches
White and Red Light
• peripheral line crossings occurred the lest
Light Exposure
Adiyodi 1981
• Increase activity unless able to retreat
• Most intense light at the centre of the tank
• The cockroaches stayed on the periphery
Future Implications
• Exhibit more movement in dark light conditions
• Direct influences of red and white light
References• Adiyodi, K. G. 1981. The American Cockroach.1st edn. Netherlands: Springer.
• Harker, J. E. 1956. Factors controlling the diurnal rhythm of activity of Periplaneta americana L. Journal of Experimental Biology. 33: 224-34.
• Koehler, P. G., Agee, H. R., Leppla, N. C. and Patterson, R. S. 1987. Spectralsensitivity and behavioral response to light quality in the German cockroach (Dictyoptera blattellidae). Annals of the Entomological Society of America. 80: 820-822.
• Walther, J.B. 1958. Charges induced in spectral sensitivity and form of retinal action potential of the cockroach eye by selective adaptation. Journal of Insect Physiology. 2: 142-151.
• Wiedenmann, G. 1977. Activity peaks in the circadian rhythm of the cockroach(Leucophaea maderae). Journal of interdisciplinary cycle research. 8: 378-383.
• Image of eye diagram: http://www.gwu.edu/~darwin/BiSc151/Ecdy/Ecdysozoa.html
• Walther, J. B. 1958. Changes induced in spectral sensitivity and form of retinal action poterntial of the cockroach eye by selection adaptation. Journal of Insect Physiology. 2: 142-151.
Questions?