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Harvestman


Harvestman
Photo Information
Copyright: Steve Reekie (LordPotty) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1381 W: 144 N: 3872] (12503)
Genre: Animals
Medium: Color
Date Taken: 2008-10-24
Categories: Humorous
Camera: Panasonic Lumix DMC-FZ8, Raynox DCR 150 macro lens
Exposure: f/3.6, 1/125 seconds
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2009-03-10 15:29
Viewed: 6544
Points: 28
[Note Guidelines] Photographer's Note
I found this odd looking harvestman underneath a log in my back garden.
It was so small,and well camouflaged that it was very difficult to see,even once you knew where it was!
I've put it under the 'humourous' category because it doesn't qualify as either an insect or a spider,although it is an Arachnid.

Here is some information I copied from Wikipedia:

Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Subclass: Dromopoda
Order: Opiliones
Sundevall, 1833

Diversity
4 suborders, > 6,400 species
Suborders
Cyphophthalmi
Eupnoi
Dyspnoi
Laniatores

Harvestmen are eight-legged invertebrate animals belonging to the order Opiliones (formerly Phalangida) in the class Arachnida, in the subphylum Chelicerata of the phylum Arthropoda. As of 2006[update], over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000.

These arachnids are known for their exceptionally long walking legs, compared to body size, although there are also short-legged species. The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax, or prosoma and opisthosoma) are broadly joined, so that they appear to be one oval structure; they also have no venom or silk glands. In more advanced species, the first five abdominal segments are often fused into a dorsal shield called the scutum, which is normally fused with the carapace. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and work as antennae. This can be hard to see in short-legged species.

The feeding apparatus (stomotheca) differs from other arachnids in that ingestion is not restricted to liquid, but chunks of food can be taken in. The stomotheca is formed by extensions from the pedipalps and the first pair of legs.

They have a single pair of eyes in the middle of their heads, oriented sideways. However, there are eyeless species (for example the Brazilian Caecobunus termitarum (Grassatores) from termite nests, Giupponia chagasi (Gonyleptidae) from caves, and all species of Guasiniidae).

Harvestmen have a pair of prosomatic defensive scent glands (ozopores) that secrete a peculiar smelling fluid when disturbed, confirmed in some species to contain noxious quinones. Harvestmen do not have silk glands and do not possess venom glands, posing absolutely no danger to humans. They do not have book lungs, and breathe through tracheae only. Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. In more active species, spiracles are also found upon the tibia of the legs. They have a gonopore on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor). All species lay eggs.

The legs continue to twitch after they are detached. This is because there are 'pacemakers' located in the ends of the first long segment (femur) of their legs. These pacemakers send signals via the nerves to the muscles to extend the leg and then the leg relaxes between signals. While some harvestman's legs will twitch for a minute, other kinds have been recorded to twitch for up to an hour. The twitching has been hypothesized as a means to keep the attention of a predator while the harvestman escapes.

Typical body length does not exceed 7 mm (about 5/16 inch), with some species smaller than one mm, although the largest species Trogulus torosus (Trogulidae) can reach a length of 22 mm. However, leg span is much larger and can exceed 160 mm (over 6 inch). Most species live for a year.

In New Zealand,harvestmen are the main predators of Glow Worms.

(Further information can be found here)

Thanks for looking.
Steve

rousettus, gannu, eng55, haraprasan, valy67, ellis49, cicindela, RII has marked this note useful
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Critiques [Translate]

Hello Steve
Harvestmen common arachnids, but they are not known very well, at least as much as scorpions. I have meet them often, but I dont know their species. you captured one of them with a great macro shot and presented with good informative notes. focus, POV/OOF, composition and colors great. Thanks for sharing. best wishes, friend
Ahmet

hello Steve
super composition
great macro with good colours
great details of the spider
greeting lou

  • Great 
  • gannu Gold Star Critiquer/Gold Note Writer [C: 988 W: 4 N: 3277] (14761)
  • [2009-03-11 3:01]
  • [+]

Steve, Too close shot perhaps result in slightly OE and OF. Thanks for such a long note. Ganesh

  • Great 
  • eng55 Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 1256 W: 42 N: 1976] (5892)
  • [2009-03-11 5:19]

Hi Steve,
Excellent close up.I liked POV,framing BG,visual impact and especially DOF you managed a lot.Excellent work!
Thanks fro posting.

Namastay Steve,
A nice capture of this daddy long legs. Excellent composition and good details. Thanks a lot for sharing.

sincerely
Hara

Hi Steve,

Nice capture, good sharp view on head, natural colours. Strange but amazing spider.

Cheers
Adrian

  • Great 
  • Argus Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 5038 W: 260 N: 15594] (50626)
  • [2009-03-11 7:57]

Nice macro Steve!
Interesting depiction of a Harvestman taken from a frontal POV that shows the curious jaw structure. The humourous category could also apply to the appearance as it looks like one of the original illustrations of Alice in wonderland!
Cheers,
Ivan

Hello Steve !
Wow, lucky I didn't open this one just before going to sleep, would have given me nightmares ! I'm terribly afraid of spiders (I know it's stupid, but well..) and even if this is no ture spider, it looks really impressive and monster-like. Excellent sharp details, and such a great pose - he seems to be ready to jump on you ! I also like the natural colors, the composition, the POV. Very well done !
Valérie.

Hi Steve,

A very interesting animal and photo. A different POV than the typical Harvestman shot, works for me.

Your comment about not having an appropriate category points up that we need to have a LOT of new categories added, as there are many subjects that aren't covered with the current category list.

Thanks,
John

  • Great 
  • honza Gold Star Critiquer/Gold Note Writer [C: 533 W: 0 N: 720] (4197)
  • [2009-03-11 14:27]

Hi Steve. Very good and spookish picture of the "spider". I like sharp details and composition very much.
Jan

Hi Steve,

nice macroshot of these spider with good details and beautiful natural colours.

Gert

Hello Steve,
you have captured the harvestmen in a very nice way,
the DOF is maybe abut shallow because of the extra lens and
you need to go to F8 for a decent DOF in this close but you had no room for a smaller aperture so it's only to accept it.
The head and the front legs are in very good focus.
I like the composition and POV too.
Well done, mf.
Gert

Yes, this one looks very dangerous! Especially when we look at its mouthparts :) Nice to know that this species hunts for larvae of Diptera.
Anyway, I like this capture a lot - it is great documentary picture (not too many Opiliones in TN gallery...), perfect POV (these mouthpars are great! :>), and very nice technique (DOF, sharpness, ect.).
TFS and I am waiting for you next pictures :>
Radomir

  • Great 
  • RII Gold Star Critiquer/Gold Note Writer [C: 481 W: 0 N: 895] (2862)
  • [2009-12-13 10:47]

Hello Steve.

Great capture macro,excellent POV and composition, very nice naturals colors.

Thanks...RICARDO.

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