Seeing the World through Other Eyes

I came across this little beauty this afternoon at Van Patten Woods:

Rainbow Bluet (Enallagma antennatum), Van Patten Woods FP, Lake Co, IL 6/21/2014

This is a female Rainbow Bluet, one of our prettiest damselflies. One of the neat thing about damselflies (and dragonflies) is their ability to navigate by polarized light. (1) Since polarization varies across the sky depending upon the sun's position, this is a very useful trick. Water reflects light in a polarized fashion as well, which is probably useful for a dragonfly as well. Other insects can do this as well:

Bibio albipennis, Lyons Woods FP, Lake Co, IL 6/2/2014

Golden Northern Bumblebee (Bombus fervidus), Gander Mt. FP, Lake Co, IL 8/3/2013

Many of them can also see ultraviolet light, which bees use to locate the appropriate flowers and the nectar within those flowers. (2) These guys have evolved strategies to take advantage of this ability:

Six-spotted Orbweaver (Araniella displicata), Ryerson FP, Lake Co, IL 5/31/2014

Orbweaver spiders place UV-reflective decorations within their webs to actually attract prey -- bait, if you will. (3)

When you're wondering what your favorite pet thinks about the world, it's worth remembering that he or she almost certainly doesn't perceive the world the way you do. So much of ecology would be completely hidden without the tools we have, based on theory hashed out by generations of physicists, built by engineers for those biologists with the imagination to conceive of a world that looks completely different than the one we see.

(1) Meyer, E. P., & Labhart, T. (1993). Morphological specializations of dorsal rim ommatidia in the compound eye of dragonflies and damselfies (Odonata). Cell and tissue research, 272(1), 17-22.

 

(2) Guldberg, L. D., & Atsatt, P. R. (1975). Frequency of reflection and absorption of ultraviolet light in flowering plants. American Midland Naturalist, 35-43.

 

(3) Craig, C. L., & Bernard, G. D. (1990). Insect attraction to ultraviolet-reflecting spider webs and web decorations. Ecology, 616-623.