New Species of 'Decoy' Spider Likely Discovered At Tambopata Research Center

The decoy spider constructed out of leaves.
Image by Phil Torres

From afar, it appears to be a medium sized spider about an inch across, possibly dead and dried out, hanging in the center of a spider web along the side of the trail. Nothing too out of the ordinary for the Amazon. As you approach, the spider starts to wobble quickly forward and back, letting you know this spider is, in fact, alive. 

Step in even closer and things start to get weird- that spider form you were looking at is actually made up of tiny bits of leaf, debris, and dead insects. The confusion sets in. How can something be constructed to look like a spider, how is it moving, and what kind of creature made this!?

It turns out the master designer behind this somewhat creepy form is in fact a tiny spider, only about 5mm in body length, that is hiding behind or above that false, bigger spider made up of debris. After discussing with several spider experts, we've determined it is quite probable that this spider is a never-before-seen species in the genus Cyclosa. This genus is known for having spiders that put debris in their webs to either attract prey or, as in this case, confuse anything trying to eat them.

The actual spider (left) and examples of the constructed, false spiders (right).
Images by Jeff Cremer and Phil Torres.

You could call it a spider decoy, in a sense. The spiders arrange debris along specialized silk strands called stabilimenta in a symmetrical form that makes it look almost exactly like a larger spider hanging in the web. Studies have found that some Cyclosa species have a higher survival rate against potential predators like paper wasps because the wasps end up attacking the debris in the web rather than the spider itself. As seen here, Cyclosa can make debris look a bit like a spider, but not nearly as detailed as the spiders found at the Tambopata Research Center which have a complex form that actually looks like a bigger version of themselves, complete with legs and all.

After asking other experts, I cannot seem find another example of an animal creating a bigger, decoy version of itself to escape predation, making this species not only interesting to taxonomists naming new species but to those who study animal behavior, as well. 

After 3 days of searching we found about 25 of the spiders found in one floodplain area surrounding the Tambopata Research Center. Extensive searches in other areas did not turn up any of the spiders, showing that they have a rather restricted range, at least locally.