by Matthew Cobb
If you’re phobic about Arachnids, move along quickly!
These things popped into my Twi**er feed. The first I can’t embed as it’s one of those gif-esque 6 second Vine thingies that Twi**er have invented and WordPress doesn’t like the embed script.
Here’s the link and here’s a verbal description: chap/chapess (user ‘Paglo?’) pokes a furry looking bit of grot in what looks like the edge of a swimming pool. And then something happens, involving Opiliones (or harvestmen, or daddylonglegs – for more common names, see at the end)…
Here’s another example of the same phenomenon, from Arizona:
and another, less dramatic:
My copy of the superb Harvestmen: The Biology of Opiliones by Ricardo Pinto-da-rocha, Glauco Machado and Gonzalo Giribet is at work, so I can’t investigate why these species of Opiliones apparently have an affinity for grouping together in furry objects (though if it’s for camouflage it would seem pretty damn effective!). Can any arachnologists (opilionogists?) chip in?
I can’t emphasise enough how good that book is, by the way: you can read my rave review from the Times Literary Supplement here. Earlier in the year, arachnologist Chris Buddle tw**ted the best bits as he read it, under the hashtag #OpilionesProject. You can read 10 fun facts Chris learned along the way here.
Here are some of my own fave things about harvestmen, taken from some of the slides for my second year lectures on invertebrates.
• 6000 species known (really 10,000?)
• Found up to 4000m
• Virtually nothing known about African, tropical Asian or Amazonian species
• Earliest known specimen from the Rhynie chert in Scotland, about 400 MY old (fantastic pics here).
• Omnivorous, but many carnivorous (though not venomous).
• Can eat fungus or bananas or cappuccino mousse…
• Masticate food (unlike spiders)
• Generally XY sex determination
• Internal fertilization – male penis is everted version of ovipositor
• Not all of them look like classic form. Can be short and stubby or have very nasty grabby chelicerae (front appendages shared by spiders, scorpions, sea spiders etc)
• Generally only 1 pair of eyes
• Do not produce silk
• No pedicel connecting tagmata, externally segmented abdomen
• Latin name comes from Opilio (”shepherd”), allegedly because shepherds in some parts of the world walked around on stilts (honest!).
• Various common names, many of which have to do with harvesting:
Kosec (“reaper”) – Slovakian,
Hooiwagen (“haywagon”) – Dutch,
Pedro – Spanish (St Peter’s Day)
Zatomushi (“blind bug”) – Japanese
Lukki – Finnish (means nothing!)
h/t Morgan Jackson (@BioInFocus) and Bug G. Membracid (@bug_girl)