Entomological Etymology 8: daddy long-legs
I just learned that some people call a crane fly a daddy long-legs, while for me a daddy long-legs is more.. Spidery.
Check out my video on “mosquito hawks” to learn all about the FLYING type of daddy-long-legs. Today, we’ll focus on the flightless kind. So what even are they? Are they spiders, or something else? Even though I love bugs, I’ll be honest with you, spiders and their look-alikes still give me the creeps. But that’s personal bias talking, and I’m a bug professional. So let’s get into it!
It turns out, both! One group of creatures commonly called daddy-long-legs are also commonly known as “cellar spiders”, since they like to eat the bugs in your basement. They are indeed actual spiders, of the Pholcidae family. Pholcidae is of Greek origin, coming from “pholkos”. Most scholars seem to think “pholkos” means “squint-eyed”. Like most spiders they have 8 eyes, but the Pholcid spiders have six of their eyes squished together into groups of three. So it looks like they have two big eyes, and then two tiny eyes in the middle. This kind of makes them look like a human skull, and they are also called skull spiders!
So what about the third type of daddy-long-legs, the type that I actually called by that name where I grew up
These critters are a type of arachnids, but they aren’t actual spiders. You can tell the differences because they have no waist. All Arachnids have two major body segments, a cephalothorax (Greek: cephalo “head” and thorax “chest) also called prosoma (Greek: pro “first” and soma “body”), plus an opisthosoma (Greek: opisth “rear” + soma “body”). In spiders, the prosoma and opisthosoma are constricted in the middle, giving them a tiny waist. But these guys have no waist, making it look like their prosoma and opisthosoma are part of one ball-shaped body segment. They make up an entire Order of arachnids, commonly called Harvestmen, or opiliones.
So the name “daddy-long-legs” can refer to a fly, a spider, or a harvestman depending on who you ask. This chart shows the evolutionary relationships between the three different types. None of them are especially close relatives, they just ended up with long skinny legs through convergent evolution!
Why harvestman? Well, they do become more common in the fall, typical harvest time. And opilione comes from Latin and just means “sheep-master” or shepherd. So we have an agricultural theme. Supposedly the long skinny legs of the opilione resembled old-fashioned shepherds, who walked on stilts to traverse marshes and get a better view of their sheep. Opiliones also like to live in fields which were considered good grazing environment for British sheep. I should note that some Harvestmen actually have short legs!
Just like the name daddy long-legs is used for flies, spiders, and opiliones, so too is the myth that these creatures have a horrific venom. In fact, none of them are especially venomous.
Spiders and opiliones do have tiny fangs, like all members of the chelicerate group of arthropods. Chelicerates are named for their fangs, from Greek “khele” claw or hook + “keras” horn. The Pholcids and opiliones only have weak as far as arachnids go. By the way, opiliones actually have a special defense: they can emit bad smelling benzoquinone chemicals to ward off predators. So leave em alone!
So there you have it. When you’re talking daddy long-legs, you might have to clarify which type of critter you actually mean!
Words: daddy long-legs, Pholcidae, pholkos, cephalothorax, prosoma, opisthosoma, harvestman, opilione, opilio, chelicerate, khele, keras
Sources:
Amateur Entomologists’ Society
Suzanne Ragga, 2015. Listverse.
Steve Reece, 2009. Homer’s Winged Words,.
Glauco Machado et al. Laboratory of Arthropod Behavior and Evolution.
Norman Larsen. Biodiversity Explorer
Rare Historical Photos.com
Machado et al. 2005. J. Chem. Ecol.
Douglas Harper, Online Etymology Dictionary
