In nature, as elsewhere, not everything is what it seems. We're highly impressed with the camouflage so commonly used by the natural world to conceal prey from predators and predators from prey. Yet sometimes this isn't as clear-cut as it appears. A case coming from Down Under—otherwise known as Australia—is instructive.
Crab spiders often lurk on flowers, ready to pounce on unsuspecting
pollinators. Spider color often blends beautifully with that of the particular kind of
flower inhabited. But in the Australian study, a white crab spider on white petals was
nearly invisible to human eyes. Ah, but pollinating insects also perceive ultraviolet
light, and it turns out that the spider is conspicuous at those wavelengths. It also
turns out that pollinators are more attracted to patterned flowers than to plain, and
the spider turns a plain flower into a patterned one. Thus the best of two
worlds—invisible to predators and an attractive lure to prey. Do we have similar
spiders in our Chihuahuan Desert? The best answer we can give is, our ignorance is
overwhelming! 
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Heiling, A. M. M. E. Herberstein, and L. Chittka. 2003. Crab-spiders manipulate flower signals. Nature, 421:334.