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.
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