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 Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>