(North America- "Daddy Long Legs").
Harvestman, as I'm sure you are aware, are only superficially similar to true spiders in that they have eight long legs. Thats about it really.
Their body is an amalgam if you like, of cephalothorax and abdomen, (unlike the spiders' disinct constriction between the two body parts), producing what I know some people to refer as a potato-shaped body - a very good description.
Harvestman only have two eyes (unlike the true spiders' 8 or 6), raised on a turret on their body, and they lack the ability to produce silk or venom.
They belong to the order Opilione and are widely distributed around the UK in about 26 different species (I think).
They eat pretty well anything, both dead and alive, and also have somewhat the reputation for always having a raging thirst, seeking out damp surroundings and often sucking up the moisture from fleshy plants or prey.
Harvestman have 4 very good defence mechanisms against predation.
- The first is that they are packing heat, in the form of a foul-tasting liquid, which allegedly smells of a cross between strong walnuts and horseradish. Predators find this substance most noxious.
- Second (aptly I suppose) is their ability to shed legs, rather like a Crane Fly does. They can shed a number of legs, but certainly NOT their second pair of legs (i.e. second from the front of their body). These pair of legs are the longest pair (always) and are PACKED with sensory organs with which the Harvestman makes sense of its surroundings.
Uniquely, also, the male sex-organs are located on this pair of legs.
- Thirdly is their dull brown/grey camouflage and very thin (almost invisible when at rest and pressed against a surface) legs.
- Fourthly and lastly, the Harvestman are nippy little blighters, and can hot-foot it away from many predators.
Finally, in case you wondered - Harvestman are so-called because they tend to appear at harvest-time, and were first studied and documented by biologists around the time of harvest. (Obvious really)!
I apologise for the rather poor picture I took tonight. As I described above, Harvestman can really turn on the gas if alarmed, amd this one did just that, leaving me a photo of its arse and not much else.
NB. For the pedantic amongst you, Harvestman belong to the CLASS ARACHNIDA, the SUBCLASS DROMOPODA (Harvestmen, Scorpions, Pseudoscorpions and Camel Spiders) and the ORDER OPILIONES.