Preferences of lab-raised and wild Armadillidium vulgare exposed to different colours of light

Kelsey Eatmon, Amie MacDonald and Elise TessierBIOL 3401

November 2013

Outline

• Background information• Goal of our experiment• Hypotheses• Materials and Methods• Results• Discussion• Conclusions

Background Information

• Pillbugs– Terrestrial isopods – Modified lungs – Sensitive to high intensities of light – Believed to be negatively-photosensitive

http://en.wikipedia.org/wiki/Armadillidiidae

Goal

• Determine if the photosensitivity of pillbugs raised in the wild and lab-raised pillbugs will increase as the wavelength of light decreases

Hypotheses

• Lab-raised pillbugs and wild pillbugs will prefer the dark environments

• Lab-raised pillbugs will be less photosensitive to a high intensity light than wild pillbugs

• Photosensitivity will increase as the wavelength of light decreases

Materials and methods

• Wild pillbugs were collected by Silver Lake in Sackville, New Brunswick– Maintained in a dark environment at an outdoor temperature

Materials and methods

• Lab raised pillbugs came from the Animal Behaviour Lab at Mount Allison University– Maintained at room temperature – Regularly exposed to the light from the windows

and the overhead lights (~340 Lux)

Materials and methods

• Experimental Design – Elongated plexiglass chambers– One lamp placed on either end of the chamber– Filters used to produce the blue, yellow, and red light (43

Lux)

Materials and methods

• 10 wild pillbugs and 10 lab-raised pillbugs tested separately

• Monitored under sequential combinations of light colours

General preference of lab-raised vs. wild pillbugs

Specific colour preferences

Visible light spectrum:DARK → RED → YELLOW → BLUE → WHITE

Wild pillbugs:DARK → RED → BLUE → YELLOW → WHITE

Lab-raised pillbugs:• Did not show pattern

Discussion

• Acclimation

• Social Behaviour– Aggregation patterns

http://www.floridapest.com/pest_guide/landscape-pest/sow-bug.html

Discussion

• Appearance of colours– Blue appears darker than yellow– Colours may not appear the same to pillbugs

• Compound eye

• Desiccation

http://www.flickr.com/photos/54475261@N02/6736802539/

Conclusions

• Wild pillbugs followed the predicted pattern– Exception: blue and yellow

• Lab-raised pillbugs did not exhibit predicted behaviour – Acclimated to higher light intensities

Questions?