How I Discovered a South American Slingshot Spider
By Lary Reeves
One muggy night in May 2013 near the Los Amigos Biological Station, I was slogging through a swamp with Geoff Gallice, a fellow graduate student at the University of Florida, and artist Lindsay Whelan, trying to get my hands on a couple of juvenile spectacled caimans and dodging bullet ants on the foliage. I think I was watching for bullet ants when I noticed a web that was pulled back from the center, making a cone. A spider was holding the web in a tensed position along an anchor line. I looked a little closer, called everyone else over, and presumed that the spider released the tension in the web to capture prey. As soon as the words left my mouth, a mosquito flew by and the spider released the web, slingshotting towards it.
The web was similar in design to other orb webs — the two dimensional webs you might find in your garden, or on the eaves of houses to capture flying insects. The big difference was that the center of this web was pulled back and anchored to the surrounding vegetation by a line that extended from the center of the web to the anchor point.
We later observed additional spiders near the Tambopata Research Center, and we shot a video — with help from Phil Torres — and released it on YouTube on January 8, 2014. Since then it has been viewed nearly 300,000 times.
The spider, like the orb weavers most people are familiar with, sits in the center of the web, then stretches the web towards the anchor point by crawling towards it while bundling up slack in its legs, setting the slingshot trap. It then somehow senses that a fly is within reach and releases the tension on the anchor line, propelling the web and itself towards its prey. If the spider misses, it seems to be able to reset the web-trap fairly flawlessly and with great ease.
All of the spiders we’ve observed have been smaller than 1cm in size. We’ve identified them as species in the family Theridiosomatidae, likely in the genus Naatlo. The range for the family seems to be throughout the Neotropics from Central America down towards southern South America.
Since the video was released, the slingshot spider has been featured in the following articles, among others:
Next summer we plan to return to the same place to investigate another spider, the decoy building Cyclosa. While most of our activities will be focused on them, we will certainly be paying attention to the slingshot spiders while we’re down there!
Lary Reeves is a photographer, conservationist, National Science Foundation fellow, and graduate student. He received a master’s degree in entomology at the University of Florida, where he is currently working towards a PhD under Dr. Akito Kawahara. His research focuses on conservation issues of tropical forests. Currently, he is investigating invertebrate-based methods of sampling vertebrate diversity. Lary can be reached at firstname.lastname@example.org, or you can follow him on Twitter at @BiodiversiLary.