Salticidaes Vision(jumping

spiders)

Group 1: Chingyee, Hilmi, Anthony

Eye Structure

Colour Vision

Survival Methods

Summary

Overview

Eye Structure

Trapezoid formed by anterior lateral eyes (ALE) and posterior eyes (PE) such that the shorter edge is posterior (dorsal view)

Eye Structure

Internal structure of the eyes

Jumping Spider Colour Vision

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Tetrachromacy◦ 4 colour cones◦ Sensitive from 300nm to 700nm

Layered retina◦ 4 layers◦ Outer 2 detect UV◦ Inner 2 detect green light

Colour Vision

Particularly sensitive to green (520-540nm) and UV (360nm)

Colour of light affected ◦ Accuracy◦ Distance

http://www.youtube.com/watch?v=0ZwTEcbX1Eg&feature=player_embedded

Experiment!!

Survival Methods

Salticidaes (jumping spiders) gauge depth cues from the amount of defocus (comparing a blurry version of an image with a clear one)

Defocusing for depth perception

Taking into consideration the layers' respective distances from the lens of the eye, incoming green light is only focused on the deepest layer, while the other green-sensitive retinal layer receives defocused or fuzzy images

The fuzzy layer is proportional to the distance an object is to the lens of the eye.

Defocusing for depth perception

ALE used in providing crucial warning to the spiders.

If the spider could detect the motion, it would respond by backing up rapidly, usually lifting up a couple of legs in a defensive posture

3 groups of spiders (AME painted, ALE painted and no paint on the eyes)

Experiment!!!

The spiders were put into an enclosure with an iPod touch. On the screen was a black dot.

When the spider was looking toward the screen, the researchers pressed play, and the dot either

1.expanded quickly (as if it coming toward the spider) or

2.contracted (as if receding).

Experiment!!!

ExperimentGroup 1 Group 2 Group 3

Location of paint

Anterior Median eyes

Anterior Lateraleyes

No paint on eyes

Results Defensive posture

No response Defensive posture

Labels of inner part of the eyes The use of each eyes

Sensitive to green and UV Layered retina

Defocus Motion detection

Summary

Thank you for your attention!

http://jumpingspidersma.wordpress.com http://wikis.evergreen.edu/m2o1112/index.p

hp/Spiders_and_scorpions http://www.earthtimes.org/scitech/green-lig

ht-jumping-spiders/1789/ http://jeb.biologists.org/content/51/2/443.ful

l.pdf http://research.amnh.org/iz/blackrock2/famil

ies/salticidae.htm http://salticidae.org/salticid/diagnost/genera

l/eyes.htm

Bibilo