Net-casting spider

Fulgorid leaf hopper caught in the web of a net-casting spider

Lots of cool arthropods here in the Osa peninsula of Costa Rica! Here is the famous net-casting spider (family Deinopidae), also called the ogre-faced spider because of its enlarged median eyes. Deinopids are nocturnal hunters, hanging upside down to ambush small insect prey . They spin an array of corrugated threads into a trapezoidal shape and hold the web with their four front legs, ready to thrust forward to entangle prey in the sticky threads. After observing the spider for a few minutes it changed the formation of its web to be more elongated, dangling back and forth elastically before bursting forward to catch a fulgorid leaf hopper that was attracted to my head torch. This was the first time I have ever seen a net-casting spider catch prey, and it was fascinating to use my magnifying lens to see the texture of the threads and how they wrapped around to immobilize the leaf hopper. About a minute later the spider rapidly spun the prey tightly and followed a thread to its daytime hiding spot under a leaf, assuming a more cryptic position to devour its prey.

Photographed ‘in situ’ [1] with exception of the leafhopper

In situ under ultraviolet light, unedited image.
Macro of the spider’s threads

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