About six months ago, a graduate student at the Georgia Institute of Technology first spotted a mysterious web unlike anything scientists had seen before: Each one of the weird webs was a tiny sphere surrounded by a circular fence less than an inch (2 centimeters) in diameter.
This mysterious formation was found underneath a tarp at the Tambopata Research Center in Peru. Despite consulting with several experts — who made several wild guesses, from moths to slide molds — no one knew what built the structure, or for what purpose. One of their first hypotheses was that the blobs in the middle were spermatophores, or packages filled with sperm and nutritious food that would attract female spiders. But over the course of a week, they didn’t find any signs of females coming to eat the packages.
Return to the scene
About a month ago, the researchers finally got a chance to go back to the spot where they found the webs. They searched around the area where the first ones were found, eventually spotting 45 to 50 of the weird formations. They then spent day and night studying the structures to see if they could find any signs of activity. See images of these mysterious contructions here.
Mystery finally solved
Finally, the researchers removed three of the structures from a tree and put them under a glass. After about a week, the mystery was finally solved when two spiderlings came out of two of the structures, and later, a third spiderling hatched from the formation. The researchers still don’t know what types of spiders (neither family nor group) make the webs.
Here, the macro video footage of the spider which hatched from one of the circular web structures found near our lodges in Tambopata, Peru:
The purpose of the fence also remains a mystery, though the researchers have a few theories.
During one of their days of observation, they saw an ant approach a tower and then turn back. The web towers are found on Cecropia trees, which have a symbiotic relationship with ants, so one possibility is that the fence defends against ant invaders that live on the tree. The researchers also saw some mites crawling around the towers. So, it could be that these fences are designed to capture mites, so that whenever the spiderling hatches, it could have something to eat right there. It’s even possible that the spiders use some chemical attractant, such as a mite pheromone, to lure them to the webs.