SPIDERS page 7--Spitting Spiders
This page was born 4/30/2005.  Rickubis designed it.  (such as it is.) Last update: 5/17/2012
Images and contents on this page copyright 2002-2012 Richard M. Dashnau

Here are my other Brazos Bend pages:  
Alligators at Brazos Bend State Park Page 1  Critters at Brazos Bend State Park Page 1
Alligators at Brazos Bend State Park Page 2  Critters at Brazos Bend State Park Page 2
Alligators at Brazos Bend State Park Page 3  Spiders page 1
Alligators at Brazos Bend State Park Page 4  Spiders page 2 (Nephila clavipes)
Alligators at Brazos Bend State Park Page 5  Spiders page 3
Alligators at Brazos Bend State Park Page 6  Spiders page 4 (Jumping Spiders)
Alligators at Brazos Bend State Park Page 7  Spiders page 5 (Orb Weavers)
Alligators at Brazos Bend State Park Page 8  Spiders page 6 (Fishing Spiders)

Spiders are interesting just because they're spiders. But ,there are some who are unique, even among arachnids. The spitting spiders are one example.

(Note--In studies that I've found since I wrote  this, and direct communication with Dr. R.B. Suter; there is increasing evidence that there is no toxic component in the "spit" of scytodes. It has been shown that the spit can actually contract so that besides gluing down the target organism there is also a tightening effect. This could cause the limbs of the prey to contract and give the illusion that the prey was "curling up" and dying. Look for these studies online:Spitting performance parameters and their biomechanical implications in the spitting spider, Scytodes thoracica. Suter RB, Stratton GE link here; and  Clements R, Li D. 2005. Regulation and non-toxicity of the spit from the pale spitting spider Scytodes pallida   Here's a study of the hunting strategy of spitting spiders: Gilbert C, Rayor LS. 1985. Predatory behavior of spitting spiders (Araneae: Scytodidae) and the evolution of prey wrapping. Linked here.
R. Dashnau 09/02/2010  

March 20 2005  The picture below (see SNARED) is a macro photograph of a Spitting Spider (scytodes sp.). with some newly-caught prey. The victim is a spider that I could not identify.  Up until now, in the years since 2002 (when I started capturing spiders with photographs), I've taken pictures of Scytodes 5 times. These were rare occasions, and after I identified the spider (some of the pictures were pretty bad for a number of reasons), I especially looked for them. Even so, I only took pictures 10/20/02; 10/24/03; 07/19/04; 02/19/05; and 03/08/05.  So, this was obviously not a very common occurance. Now, here I have found another one in my apartment! (Don't even TRY to picture what my home looks like.  It would scare most normal people.)
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                                                                                            SSNARED!
The spider was lying still in a corner, about 4 feet up the wall. I took a few pictures, and left the spider there. It was in the same spot the next morning, although it was positioned differently. For all I know, it could have run every corner in the apartment and returned. It was *still* there the next evening--and that's when things got interesting. I found another spider scurrying across my floor. I caught it, and tried to take some macro photos (it was pretty small) so I could identify it. Having done that (I found out later that my lighting malfunctioned.), I wondered what would happen if I put the new spider on the wall near the Scytodes.  Bear with me--this was really interesting.
I quickly set up my tripod and my C-770 ( I thought macros would be much better than my video camera. I only have one tripod, so had to choose.) I rigged a small flashlight as a spot on the Scytodes. With everything set up, I placed the "new" spider on the wall, and watched with my finger on the camera button.  Today's RICKUBISCAM shot shows the outcome. The newcomer is snared and covered by a net of threads. The Spitting Spider is cleaning one of its legs. That image was one of the few stills that I shot. Below is a sequence of frames from the video clip I shot of the attack. Because I was in "super macro" mode, depth of focus is very shallow, so the spider moved out of focus from time to time.

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            PREY MOVES UP ON RIGHT                                       PREY'S LEG TOUCHES                                      SCTYTODES FACES PREY                                  SYTODES LEAPS SIDEWAYS                             SCYTODES BEGINS SWING
The unknown spider moved up past the scytodes, until one of its legs brushed the scytodes' leg. The scytodes turned towards the spider, and leapt sideways (although this could have just been falling). It swung in an arc (with its fangs facing the center of the arc) until it landed under the unknown spider. Then it slowly moved back up towards the unknown spider. During this time, the prey became ensnared, but still struggled. It seemed to me that the scytodes used its "spit" to swing on.

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                 SCYTODES LANDS BELOW                                 SCYTODES COMES UP                                         REARS BACK-MORE SPRAY?                             MOVES FORWARD AGAIN                                   FANGS TO THE ABDOMEN!
The scytodes slowly moved towards the prey, and then reared back with its forelegs moving quickly. Perhaps there were more strands being deposited at this time. Finally, as the prey struggled, I can clearly see the scytodes administer a bite to the prey's abdomen! I can even make out tiny bumps when the scytodes withdraws after the bite. Immediately after the bite, the prey stopped moving, and the scytodes casually cleaned its forelegs.  The two images below (CLEAN FIRST; READYTO EAT) are two more crops from still photos I shot. This was...VERY cool!

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                                                CLEAN FIRST                                                                                                         READY TO EAT
Now, if you've seen my previous information about the scytodes (see below), then you might have seen my references to the work done by professor R.B. Suter, of Vassar University; and perhaps gone to see his amazing high-speed video clips of the scytodes' spitting patterns. Most of the literature that I've been able to find on the scytodes indicates that there is some kind of "venom/glue" mixture being expelled by the spider.
Professor Suter's research shows so far that the "spit" is a combination of "silk and a viscous liquid". He has work in process which will detail some of this research, and which I hope I will be able to see after it's published. There may be no evidence of "venom" as an active ingredient in the liquid snare. Thanks again to Professor Suter for taking the time to converse with me about this.  What I've been able to capture in this short film clip may also show this. The scytodes' bite seemed to be what actually stopped the prey from moving--or killed it. I thought it was also interesting how the scytodes didn't swing with its abdomen at the center of the arc--as most spiders would--but with its head facing the center. This is perhaps further proof for the silk properties of the spit, with the spider using it as a tether.
If you'd like to see the video clips yourself, here are links to three flv video versions: Normal Speed-- 392kbslow motion part 1-- 707kb ; slow motion part 2-- 343kb. 
And here are two larger wmv videos (encoded 5/17/12) of the same:  
Normal Speed-- 4.0mb ; "slow motion"-- 3.4mb
The spider remained to feed on its catch for another day. Then, it was gone.  What a lucky shot for me, though! 

February 20 and March 08 2005  The image below (SIX EYES) shows 3 sets of double eyes on the face of a spider. The double eyes are also called "diads". This arrangement of 6 eyes can help identify a few spiders. One of the spiders with a similar arrangement is the somewhat hazardous Brown Recluse, loxosceles reclusa . However, my subject is NOT one of those. I have had these spiders turn up from time to time in my bathroom.
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                                                                                                    SIX EYES
When I identified my first one (in October of 2002) I was relieved, and excited. My occasional visitors are Spitting Spiders! (scytodes species) The Spitting Spider earns its name from its specialized method of catching prey. When it detects a potential live meal, the Scytodes slowly moves towards it until it gets within range (1-2 cm. according to Biology of Spiders, by R. Foelix); and then it sprays two streams of a glue/venom mixture from adapted openings at the base of its short fangs. This is sprayed in a zig-zag pattern over its prey, snaring it and holding it fast. The spider is then able to attack the immobilized prey with its short fangs.
On Feb. 20, I found a Spitting Spider looking down at me from a corner of my shower. I captured it, and took a few pictures. These spiders, when caught in the light, usually don't move. Once this one decided it wanted to move, it moved quickly! I had a really hard time focussing the camera on it as it kept running up my arm (see ON RICK'S WRIST, below).  You can see by comparison with some of my wrist hairs that the spider isn't very big.
I was finally able to convince it to climb onto the wall, and got another photo against the molding (see TOP VIEW, below). I also took a short video clip (flv video 408 kb) 
(wmv video encoded 5/17/12 3.1mb) (also see the frame from the clip WALL WALKING, below).  Notice how it moves, sensing with its long forelegs.  Note the short round abdomen, and the mottled coloration. This is NOT a Brown Recluse.  I let the spider wander off while I went back to my business.
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                       ON RICK'S WRIST                                                             TOP VIEW                                                           WALL WALKING                                               OBLIQUE VIEW
                                                                                                                 video clip (flv video 408 kb) 

                                                                                                     (wmv video encoded 5/17/12 3.1mb) 
A few days later, I was moving some pants in my closet, when I was surprised when a spider appeared from a folded pair of blue jeans and started running. I rotated the jeans as the spider ran, watching it long enough to identify it as another (or maybe the same?) Spitting Spider. I carefully folded the jeans back to the way they had been, and the spider found its way back into a large fold, and I put the jeans back into the closet. On March 8th, I decided I didn't have enough good pictures of the scytodes, so I took a chance and moved my jeans again. The spider popped out, and I captured it. I left it in the refrigerator for a little while, and was then able to photograph the spider while it warmed up. Now taking a closer look (see OBLIQUE VIEW, above) we can take better note of the mottled coloration on the spider. Another obvious identification characteristic becomes evident when we see the spider from the side (see SIDE VIEW, below).
The carapace (top shell) is extremely humped (see HUMPBACK, below). This is unlike other spiders', and should easily identify the Spitting Spider. This spider's poison glands have developed into large, two-lobed organs. The rear lobe produces the "glue" and the front lobe produces the venom. The large humped cephalothorax allows enough space for these structures to fit.  After the spider warmed enough to begin moving more rapidly, I put it back into my closet. I assume that it's still in there, somewhere.

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                              SIDE VIEW                                                               HUMPBACK                                                  VIEW FROM THE FRONT
The scytodes are nocturnal, so most of us probably wouldn't normally get to see them hunting. It would also normally be difficult to get a close look at the glue spraying technique as well. However, this event has been filmed in close-up at high speed by R.B. Suter, of Vassar College. The stream of material is evidently redirected by manipulation of the fangs, because the streams move rapidly from side-to-side while fangs can be seen moving independently of the chelicerae. The glue is expelled by a large tapered groove which begins at the base of each fang and extends about 2 thirds of the way up. This is quite different from the structure of the fangs on most spiders, which more closely resemble a hypodermic needle--that is, with a smaller venom opening near the tip. Thanks to Professor Suter for providing this information.
In another clip, again by R.B. Suter, the glue shows evidence of elastic properties after it's been expelled. The crisscrossing strands of expelled adhesive contract enough to move inanimate objects (small wires) closer together. Professor Suter has been generous enough to communicate a few times with me about his clips, and has been very informative. Thank you, Professor Suter!  Follow this link to Professor R. B. Suter's page showing these clips (and one other, showing the lacelike pattern of the glue strands). They are amazing!
Meanwhile, I'll be going to sleep tonight, wondering at the creatures hunting in my home.

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