Spider Disguises as Bird Poop to Avoid Predatory Wasp Attacks, Study


Orb-web spider Cyclosa Ginnaga camouflages itself as a splat of bird poop in order to avoid being captured by predatorwasps, according to a study by researchers at the Tunghai University and the Endemic Species Research Institute in Taiwan.

Researchers said that the spider's silver body along with white, silken decorations on its web resemble bird droppings.

"The C. ginnaga spider has a silver body and creates a white disc on its web that functions to attract prey," the researchers said."But these characteristics may also make them conspicuous to predatory wasps," Business Insider reports.

Masquerading is a phenomenon where an animal's body color and shape imitate an inanimate object. As part of their deception process, many arachnids also add decorations to their webs, called stabilimenta - made from prey carcasses, egg sacs, plant matter or silk.

"These predators usually will form a search image to hunt for spiders, and [they] usually will not be interested in bird droppings," said lead study researcher I-Min Tso, a behavioral ecologist at the National Chung-Hsin University in Taiwan, Huffington Post reports. "Since orb-web spiders can make silks, such [an] adaptation may facilitate the bird-dropping masquerading of these spiders."

To determine whether fecal camouflage was effective, the researchers compared the appearances of spider's body and its web ornament with actual bird droppings as seen by the wasp. The researchers found that spider bodies together with their silken webs were identical to that of the bird droppings.

Then the researchers blackened either the spiders' bodies or web decorations with carbon powder to assess the frequency of the wasps' attacks. They found that the wasps were more likely to attack the eight-legged creatures when their decoration was blackened.

Silver-colored orb-web spiders aren't the only eight-legged masqueraders. Tso said that some bolas spiders and crab spiders cover themselves with silks while sitting on leaves, an example of bird-dropping masquerading.

Disguising as a bird poop is not only the weird aspect of orb spiders. The species N. malabarensis has a detachable penis that continues to excrete sperm even after it gets detached from its owner.

The findings are published in the journal Scientific Reports.

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