What Lives In Our Caves? Harvestmen

Posted October 05, 2021 by Anna & Rhiannon Davies – Cave Conservation, Cave Ecology, IYCK 2021

Harvestmen are super cool arachnids from the order Opiliones. They live everywhere in the world except Antarctica.

There are five different subspecies of Opiliones, three of which can be found in Aotearoa New Zealand. The subspecies you will most likely see in our caves are Opiliones Laniatores and Opiliones Palpatores.

Short-legged harvestman Hendea sp.

Opiliones Laniatores – The short-legged harvestmen

We have about 160 native species of Laniatores in Aotearoa New Zealand. Their legs can be up to five times the length of their body, and they use their chelicerae like hands to grasp food. Info by Soil Bugs.

Long legged Harvestman

Long-legged harvestman Forsteropsalis sp.

Opiliones Palpatores – The daddy long legs

These harvestmen have extremely long legs. A native male Palpatores’s leg-span can be up to 16cm, and his body will only be about 6mm long. Cellar spiders are often mistakenly called daddy long legs because they also have long legs, but cellar spiders are true spiders and harvestmen aren’t. Info by Soil Bugs.

What’s the difference between a spider and a harvestman?

Spiders (Order Araneae) and harvestmen (Order Opiliones) are distant cousins, but they differ in very important ways:

Spider vs Harvestman

There’s an urban legend that the daddy long legs subspecies of harvestmen is the most venomous spider in the world, but it can’t kill humans because their fangs are too short to penetrate our skin. Of course, this is completely untrue because…

  1. Harvestmen don’t produce venom
  2. Harvestmen don’t have hollow ‘fang’ type chelicerae to bite with, and
  3. Harvestmen aren’t actually spiders
Excuse me, is that your leg?

If a harvestman is threatened they can do something called autotomy. This is where an animal will shed an appendage like a leg or a tail to escape a predator. 

Harvestmen are one of over 200 species of invertebrates that can shed its limbs. If you see a harvestman with only 6 or 7 legs, you’re looking at one who’s had a close shave!

Short-legged harvestman with very clear eyes and chelicerae in a cave

This harvestmen’s two eyes and solid chelicera are easy to spot!