Bug Word-of-the-Day, Thursday 5/23
Chelicerae (kih-LISS-er-ee) — These are the last things many bugs see.
The chelicerae are jaw structures found in spiders, scorpions and other arachnids. They come in pairs. A single one is called a chelicera (kih-LISS-er-uh).
The shape varies a bit from one species to another, but basically the chelicerae are moving mouthparts that seize live prey.
For the sake of simplicity, we’ll stick with spiders. We’ve posted photos that show the chelicerae from two angles.
First, we have a photo showing the underside of a Mexican red-kneed tarantula. (Slightly scary seeing this predator from a cricket’s perspective, isn’t it?).
Those glossy, dark-colored, fang-like structures are the business end of the chelicerae. The sharp points are meant to pierce the prey and then inject it with venom, which is transferred through a tube-like space inside each chelicera.
(In case you’re wondering, this species is native to western Mexico. It’s NOT found in Florida except as a pet-store item.)
Next up, we have a photo of a jumping spider from the genus Phidippus. All members of this genus have iridescent-colored chelicerae, which are easy to spot when you have a good view from the front, as here.
This particular species is a bold jumping spider, Phidippus audex, and you can clearly see its green chelicerae.
The part that’s visible in this photo is actually the base of the chelicera. The base anchors the pointy, business end of the chelicera and is attached to the spider’s front body segment, which is called the cephalothorax.
Jumping spiders have a habit of moving their chelicerae constantly.
One BugWeek@UF staffer fondly recalls a jumping spider that lived in his kitchen for several months and was often seen prowling the countertops in search of prey. With the chelicerae twitching backward and forward, the little guy (or gal) looked like he (or she) was chewing gum.