"Attraction is all casinos are about. They lure you; they want to get you there. They lure people with bright lights, cheap plane tickets, inexpensive hotel rooms, great shows and great meals," says Mark E. Hauber of Cornell's Department of Neurobiology and Behavior. "The spiny spiders work the same way."
Hauber's discovery will be described in a forthcoming issue of the Royal Entomological Society journal Ecological Entomology (September 2002), in an article, "Colouration attracts prey to a stationary predator."
Bright colors and contrasting patterns should be rare in predators that use traps, since conspicuous body color is scientifically counter-intuitive in stationary predators, says Hauber. Generally, he says, animals use "sit-and-wait" tactics in their concealed traps to capture prey, and colors and patterns only alert potential prey. Yet orb-weaving arachnids, such as the spiny spiders of Australia, are brightly colored and have contrasting patterns on their bodies. Hauber found that the more colorful their backs, the greater their chances of catching prey.
"It goes against what most scientists would have thought. Color is an attracting feature," says Hauber. "While color on animals like parrots allows them to blend into the colorful rain forest, other animals use color to attract mates. In this case, the color lures prey to the web. Perhaps the color itself may look like flowers to the insects that eventually become entrapped in the web," he says.