Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Death by color: spiny spiders’ bright stripes don’t alarm but attract prey, Cornell behavior scientist discovers

14.06.2002


Like the glitter and glare of Las Vegas beckoning tourists to the gambling tables, the orb-weaving spiny spider flashes its colorful back to lure unsuspecting quarry into its web. The discovery of this lethal use of color runs contrary to the long-held belief that in the animal kingdom color is used generally to attract mates rather than to entice prey, says a Cornell University animal behavior researcher



"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.

Hauber observed spiny spiders (Gasteracantha fornicata ) in northeastern Australia. He covered the yellow-black striped dorsal surface on the spiders’ backs with ink from a black felt-tip pen. Spiders with the black dorsal surface caught less prey than spiders with their normal colorful stripes. Repeatedly he found that the blackened spiny spider always attracted and caught less prey.

"Perhaps the colors and patterns of their dorsal surface mimic the color of food -- such as flowers -- for visually oriented prey. It is also possible that the dorsal surface of the spiny spider is highly reflective in the ultraviolet part of the spectrum," he says. "Many flies, mosquitoes and gnats are attracted to bright light, and the kind of light rich in ultraviolet spectra, because these indicate the presence of field clearings adjacent to dense forests."

Hauber also learned that spiny spiders set their webs at an angle and that they sit on the underside of their webs with their backs to the ground. This suggests, says Hauber, that sun and nearby vegetation offer camouflage for the web. "Daytime web-building and hunting, along with the web placement and orientation, is consistent with behavior that attracts prey traveling from darker areas to lighter ones," says Hauber.

Funding for the research came from the Howard Hughes Medical Institute Predoctoral Fellowship program

Blaine P. Friedlander Jr. | EurekAlert

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>