This Spider Pretends to Be a Leaf!
In 2011, a team of zoologists trudging through a rainforest near Mengla, China stumbled upon four dried leaves attached to a twig. Leaves adorning a twig is completely within the bounds of normal botanical behavior, of course, but something here was slightly amiss. Thin strands of silk ran amongst the foliage. In fact, it was the silk itself that fastened the leaves to the twig, not their stems. And one of those leaves looked very peculiar...
It was a spider! And clearly, this clever creature had set the scene for the perfect camouflage.
"The observed female must have actively lifted dead leaves from the forest floor to attach them to a twig about 2.5 meters high up on a tree prior to positioning herself on a thread of silk amidst live and dead leaves," the researchers recently recounted in the Journal of Arachnology.
Enthralled with their find, the zoologists collected the arachnid, then scoured the area for more like it. Two weeks of searching turned up only one additional specimen, a juvenile. These spiders were hard to find.
Subsequent examination of the spiders at the Smithsonian National Museum of Natural History in Washington, D.C. revealed them as members of the genus Poltys, part of a charismatic family of spiders called orb-weavers.
Orb-weavers are well known for their deceptions. Only about 100 of the 46,000 known spider species actively resemble uninteresting objects, otherwise known as "masquerading", and almost all of them are orb-weavers. Some look like twigs, others like fruit, and one even pretends to be bird poop. But until now, none has been found that resembles a leaf!
The zoologists suspect the spiders to belong to an undescribed species, but can't be sure just yet.
"More material and taxonomic studies are needed to confirm this," they write.
But before such work can get underway, they need to find more of these elusive arachnids.
"One serious hindrance to this, however, is the apparent rarity of this enigmatic Poltys, confined to rainforests of southwest China, Southeast Asia, and East Asia where its cryptic habits and nocturnal lifestyle help evade not only predators, but also researchers," they jokingly conclude.
Source: Matjaž Kuntner, Matjaž Gregorič, Ren-Chung Cheng & Daiqin Li. "Leaf masquerade in an orb web spider." 2016. Journal of Arachnology 44:397–400