Order Opiliones

The order Opiliones consists of around 7,000 species of somewhat spider-like arachnids. However, they differ from spiders in several important ways. The chelicerae of harvestmen are solid and incapable of injecting venom. In addition they don't produce silk and only have a single pair of eyes. Unlike spiders they lack a distinct abdomen and therefore appear to have only one main body structure.

Although not seen as often as spiders, harvestmen are important components of many terrestrial ecosystems. Their ability to ingest solid food (unlike spiders) allows them to take advantage of many food sources not available to spiders which are basically restricted to live prey.

Many harvestmen produce toxic or noxious substances if attacked. Additional defenses may include spikes and the ability to quickly autotomize legs. In some species a detached leg may twitch for up to an hour after being shed. The advantage of this behavior to the harvestmen is that it may be able to escape while the predator is distracted.

I became more interested in harvestmen after staying at La Selva in Costa Rica. I encountered these guys regularly and was impressed by their variability in body form. One species I photographed looks like something out of "War of the Worlds". It had a pinhead sized body with ridiculously long legs. Apparently disturbed by my proximity, it swayed backwards and forwards making critical focus almost impossible. This is a behavior shared by many other long-legged opiliones.

It is widely believed myth that harvestmen are incredibly venomous. Many an innocent animal has been killed because of this belief. Repeat after me "No harvestmen can inject venom."

For an in-depth look at harvestmen check out Wikipedia.

Harvestman species 1

Harvestman, La Selva, Costa Rica IMG_4518.

Harvestman Species 2