Sunday, 8 June 2014

Spider Disguises Itself as Bird Droppings

It’s the ultimate crappy disguise: The spider Cyclosa ginnaga hides from predators by looking like a pile of bird feces, a new study says.

Study leader I.-Min Tso, an entomologist at National Chung Hsing University in Taiwan, first made the discovery walking through a research station in central Taiwan.
Spider Disguises Itself as Bird Droppings
Tso noticed Jackson Pollack-style splotches of white bird dung, which stood out in stark contrast to the lush green foliage. But when he looked more closely, Tso realized that not all of the blobs were bird droppings: A few were spiders in their webs. (Read about a spider that weaves a mysterious picket fence.)

Tso recognized the spiders as C. ginnaga, a species found in Taiwan, China, Japan, and South Korea.

As the “architects of the spider world,” spiders in the genus Cyclosa are known to create elaborate webs, using their silk to make concentric circles like Saturn’s rings and adding debris such as twigs and leaves that hide young spiders from predators. (Related: “New Spider Weaves Spider-Shaped Web.”)

Now, Tso and colleagues have discovered their defense strategy is even more sophisticated than thought.

Cornell University arachnologist Linda Rayor applauded the study, pointing out that C. ginnaga is not alone in masquerading as bird droppings.

“It’s really not all that uncommon. Several other spiders, like Bolas spiders, also use this disguise,” she said.

Web of Disguises

To find out if the bird dropping-like web confused predators, Tso and colleagues measured the webs that resembled bird feces.

Source: Here