Nov 19, 2016

Newfound Spider Species Masquerades as a Dried-Up Leaf

 In the animal kingdom, sometimes the best survival strategy is to pretend to be something you're not — either to ambush unsuspecting prey or to convince predators that you're not very tasty.

And scientists recently discovered a spider that uses a unique masquerade to hide in plain sight. It is the only known spider to have a body that bears an uncanny resemblance to a dangling, partly dried-up leaf.

The find was reported in a new study, though the spider is yet to be described and assigned a species name.

The newfound costumed arachnid is in the Poltys genus in the orb spider family, which contains more than 3,000 species and one spider celebrity from children's fiction — a Araneus cavaticus was the barn spider Charlotte from the classic story "Charlotte's Web" (Harper and Brothers, 1952).

Masquerading is far more common in insects than in arachnids. In fact, many types of insects have bodies that mimic plants. For example, the Phasmatodea order contains hundreds of species of so-called stick insects, which look like bare branches or leaves. And brightly colored orchid mantises have petal-shaped legs to complete their disguises as harmless flowers, tricking other insects into flying close enough for the mantises to snatch them out of the air.

But about 100 spider species also sport physical features that make them appear inanimate and unappetizing, like a jumble of twigs, plant debris or a messy glob of bird poo.

This is the first known spider species to be leaf-shaped. And its discovery was accidental, according to the study's lead author, Matjaz Kuntner, a principal investigator with the Evolutionary Zoology Lab at the Biological Institute Jovan Hadzi, Scientific Research Centre of the Slovenian Academy of Sciences and Arts.

The scientists spied and photographed the unusual arachnid in 2011, while looking for other types of spiders in Yunnan, China. They found the individual — a female — on a twig, surrounded by dead leaves and with no web nearby. The researchers noted that her back looked like a living, green leaf, while the underside of her body was brown, mimicking a dead leaf, and a hairy, stalk-like structure protruded from her abdomen.

The greenish-yellow underside of the spider resembles a fresh leaf, and the hairy, stalk-like structure curving from its abdomen makes it look even more like a plant.
Leaves close by the female spider on the branch were attached with silk, which hinted that she had placed them there deliberately to further camouflage herself. However, additional observations would be necessary to confirm this behavior, Kuntner told Live Science.

After searching for two weeks, Kuntner and colleagues were able to find only one more leaf-shaped spider — a juvenile male, crouching on a web. Next, they turned to museums to see if they could turn up more specimens, Kuntner said.

Read more at Discovery News

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