Spider webs

[The Snark]

(I'm looking for input here since this is nearly as broad a field as spiders themselves)

You defo don't need to keep them in anything. Mine has been pretty happy on the door. I think so long as they are catching something they won't move on.

I also read on your forum that they won't adjust a web size. Mine has, a few times.
When there was two on the door, the one i have now was really trying to spread her web around the door. This caused the other spider to make her web smaller and smaller and eventually she moved from the door up into the corner on the wall.
The spider advanced her web all along the glass of the door. But I have an active 5 yr old who likes to run up and down the hall way and use the door to stop himself. This caused him to break her web a few times. And so she adjusted! And now avoids placing lines at the bottom of the glass.
You all probably know this! But omg. How clever.
Another thing she does is repair jobs on her web. She'll cut away a section of the web thats been damaged and rebuild it.
I just can't get over how amazing these little creatures are!

The relationship between the spider, the web, and the environment is a vast intricate world unto itself. The webs may stay almost exactly the same within the entire genus or they can vary drastically from one individual spider to the next.
Shape examples
* Latrodectus, A cob web with three vertical sticky lines. Always the same with minor variations due to environmental considerations.
* Certain orb weavers. Whatever fits. A full orb or partial pie shapes, horizontal, vertical or anywhere in between.
* Agelenidae. The web is just like a baseball or football field or golf course. A groomed customized race track perfectly suited for the size of the spider, it's 'feet' adapted perfectly to the web material, and the webbing itself lending to the spider's ability to sense where there is an object in the web and tell the spider exactly where it is.
* Pholcids. Let's call their webs a demented psychosis. No rhyme, reason or planning; just a mass of threads that the spider slowly builds on throughout it's life. The spider accommodates the labyrinth the webs eventually evolve into with adroit dexterity rather than having a web working towards a master plan.

Then the purposes of the webs can vary greatly.
* To catch food of course! Actually, no. Examining the entire Anaeae order, only the minority of spiders use their webs as traps.
* Salticids never use webs for trapping prey. But they lay a web down everywhere they go as a safety line.
* Nearly all Lycosids use webs to aid in molting.
* Webs are used in a variety of ways for romance.
* Webs are used in defense, sometimes individuals and sometimes great communal webs that can confuse and repel predators.
* Most webs aren't sticky. Sticky threads require a sophisticated biology to produce.
* As a reserve food source. For example, many orb weavers will leave a glop of web in the center as they build their orb. The glob is a protein source the spider eats after the exhausting undertaking of building the web.

I'm going to leave it to others to contribute here.

 

[basin79]

There have been lab experiments with Nephila sp. All set up in identical sized enclosures.

Prey was placed in a certain part of their webs. Some top right, some bottom left etcetera. The spiders changed their webs accordingly. Gone were the circles and in their place where a small main web were the prey had always been placed.

 

[Shells]

(I'm looking for input here since this is nearly as broad a field as spiders themselves)




The relationship between the spider, the web, and the environment is a vast intricate world unto itself. The webs may stay almost exactly the same within the entire genus or they can vary drastically from one individual spider to the next.
Shape examples
* Latrodectus, A cob web with three vertical sticky lines. Always the same with minor variations due to environmental considerations.
* Certain orb weavers. Whatever fits. A full orb or partial pie shapes, horizontal, vertical or anywhere in between.
* Agelenidae. The web is just like a baseball or football field or golf course. A groomed customized race track perfectly suited for the size of the spider, it's 'feet' adapted perfectly to the web material, and the webbing itself lending to the spider's ability to sense where there is an object in the web and tell the spider exactly where it is.
* Pholcids. Let's call their webs a demented psychosis. No rhyme, reason or planning; just a mass of threads that the spider slowly builds on throughout it's life. The spider accommodates the labyrinth the webs eventually evolve into with adroit dexterity rather than having a web working towards a master plan.

Then the purposes of the webs can vary greatly.
* To catch food of course! Actually, no. Examining the entire Anaeae order, only the minority of spiders use their webs as traps.
* Salticids never use webs for trapping prey. But they lay a web down everywhere they go as a safety line.
* Nearly all Lycosids use webs to aid in molting.
* Webs are used in a variety of ways for romance.
* Webs are used in defense, sometimes individuals and sometimes great communal webs that can confuse and repel predators.
* Most webs aren't sticky. Sticky threads require a sophisticated biology to produce.
* As a reserve food source. For example, many orb weavers will leave a glop of web in the center as they build their orb. The glob is a protein source the spider eats after the exhausting undertaking of building the web.

I'm going to leave it to others to contribute here.

I've noticed my spider will lower herself down to almost the ground and then climb back up gathering all the web shes created and deposit it in the centre of the web. Do you know why she would do that?

 

[CanebrakeRattlesnake]

The only spider I currently own is a female Tegenaria domestica. In her first enclosure (and my bathroom floor where she used to live) where she had no décor she made a web in the corner with one entrance and web spread out quite a bit in the corner as well. She also seemed to cover it in pieces of coco coir, maybe to help it blend in?

In her second enclosure where I had a coyote skull and a large pieces of driftwood she made large webs all over the tank (mostly on the driftwood), but lived in a funnel on the driftwood. It had a front and back exit, and after eating she seemed to dump the cricket remains down the back exit onto the ground. She also covered this one in coco coir.

I'm going to be rehoming her to a smaller enclosure so I can more easily tell where she is so we'll see what she does in that one

 

[basin79]

There have been lab experiments with Nephila sp. All set up in identical sized enclosures.

Prey was placed in a certain part of their webs. Some top right, some bottom left etcetera. The spiders changed their webs accordingly. Gone were the circles and in their place where a small main web were the prey had always been placed.

Annoyingly I can't find anything on it. I saw it on a TV programme. The spiders were in a bank of identical enclosures. They might not have been Nephila but the rest is definitely right.

I have kept Nephila madagascariensis in captivity though within an enclosure. What I found is the spiders would sometimes curve the web. I'll see if I can find some pics of mine.

 

[The Snark]

I've noticed my spider will lower herself down to almost the ground and then climb back up gathering all the web shes created and deposit it in the centre of the web. Do you know why she would do that?

I'm partly guessing here.
1. Certain web material is the ideal food source for some spiders. The web 'glands' are a closed system. That is, once the various components are in the gland they cannot be accessed internally for any other use. So excesses of material can be set aside for future consumption. That material is designed to be dissolved by the venom - saliva of the animal sort of like a quality nutrition drink for humans.
2. Web glops are used by some spiders as decoys or camouflage.
3. Measurements. Computer simulations with Nephila have ascertained the spider can measure the web and make adjustments according to the environmental factors. See @basin79 post above.
4. Other. Spiders have evolved web sophistication over tens of millions of years. So far humans have only rudimentary knowledge of the more obvious assets and abilities. Why is Latrodectus web the nearly the strongest tensile material in the world only recently surpassed by humans in Aramid, carbon and similar fibers. Why? One would think orb weavers would have stronger webs. The answer to this may lie in their venom. Latro packs 7 different kinds of venom that reflect a vast variety of food sources from probably very hostile environments. Web content was adjusted accordingly?

Anyone else have insights ???

 

[BoyFromLA]

This article was published on February 1, 2021, and was wondering if this would be any helpful.

Spider Legs Build Webs without the Brain's Help

Researchers decode spiders’ web-building behavior for application in future robots

www.scientificamerican.com

 

[Shells]

. Measurements. Computer simulations with Nephila have ascertained the spider can measure the web and make adjustments according to the environmental factors. See @basin79 post above.

Yes, I read his post and I agreed that it was for a little snack perhaps.

Is this energy efficient though?

 

[RoachCoach]

As far as I've seen and gleaned from an embarrassing number of articles and books/videos/docus is they have a preset pattern like an instinct. I will always link the deeper look video when there is a post questioning spider web structure. They do their DD on science issues. It's all good until you get to the Deinopidae. Aside from jumpers, they are the baddest web dudes out there. The webbing of most others as you stated is like a floorplan, since they don't enjoy the visual acuity we do. Even blind people map out their environment almost instinctually. The most funny thing about webs is that the more intricate ones tend to get disassembled and recycled vs the "cobweb" silk structures. I guess If you are putting so much of your precious energy into a web, you better be damn sure it is in working order. It is all you have to gather food. Even Pinoy/Vietnamese anglers fix their nets daily. It's life or death out there.
Oh ya. Deep Look for you OGs

 

[Shells]

I just want to post this video if it will allow me. A few drops of water sprayed on her web, shes drinking the water and eating the web (i think) and repairing.

 

[Shells]

I just want to post this video if it will allow me. A few drops of water sprayed on her web, shes drinking the water and eating the web (i think) and repairing.

No, it won't allow me. Sorry

 

[Shells]

Anyone else have insights

The orbweaver has poor eye sight.
So do you think that it may be done so the spider always knows where the centre of the web is?

 

[The Snark]

The orbweaver has poor eye sight.
So do you think that it may be done so the spider always knows where the centre of the web is?

Possible, perhaps even probable. Web spinning spider eyesight is a near complete mystery. With similar eye arrangements they range from near sighted bordering on blindness on out to 180 degree effective vision at a distance of several inches. The optical part of their brain also is often very small and unsophisticated. But they appear to incorporate their eyesight, 'intelligent' legs and the setae combined with a pretty sophisticated geometrical computational ability.
What does an average web spinner actually see? Shapes and shadows? Movement? Dark and light? Colors? A something registered in the brain produced by setae combined with some, most, or all of their eyes? What does a Lycosid see with it's 300+ degree field of vision? What do salticids see with the majority of their brain connected to their two main eyes?
The best possible move is to critically observe and learn. From brainiacs at the top of their fields on down to curious toddlers, the field seems to be wide open to new discoveries.

 

[TheHound]

I have a bunch of Zygiella x-notata - Missing Sector Orb Weavers - who live around my porch and the exterior of my house, spinning webs around the outside lights, where they obviously do very well with all the insects flying around the illumination.

The missing sector of the web contains a signal line, which travels from the centre of the web to the spider's retreat. When something lands in the web it sends vibrations down the signal line to the spider, who travels down the signal line and envenomates and webs up the prey. It's thought that the missing sector is advantageous to the spider as it allows faster travel to and from the retreat and the centre of the web. Sometimes this species will construct webs with no missing sectors - this happens when the lair (and thus the signal line) is at a greater than 40 degree angle from the plane of the web. I assume in these instances the spider somehow knows that it can construct a fuller web with greater chance of snagging prey, without sacrificing the unencumbered passage down the signal line.

From the rather reference-replete and generally very interesting page I learned some of the information in this post, I found this quite interesting, in its implications for web spinning in general:

" As Zygiella is flexible as to whether it fills in the missing sector or not this seems to imply that the spider must know the whereabouts of its retreat before it builds its web. Either that or it removes the missing sector after having built a complete web. Zschokke [1] has carried out extensive work on web building by spiders and he notes that Zygiella can construct the missing sector either by never filling in the sector, reversing its direction at the sector when laying the spiral, or it can build a complete web and then remove the spiral within the sector by biting through the threads. Web building in spiders is instinctive but it does appear that Zygiella is relatively flexible in its behaviour."

I love watching them when out the front at night having a cheeky smoke, when they're active - sometimes I'm lucky enough to catch them catching prey, or spinning. Last night, around 1.30am I managed to get some video of one repairing its web. You can see at the beginning it travels pretty far down to create an anchor line at the beginning of the vid. Then it goes back up to secure more to the light fitting. In the pics I uploaded, the one labelled "1" shows the reconstructed web around 22 hours later, already depleted by the ravages of nature, ready to be built again, as they do daily. You can just see an anchor line going between the web and the little thin pipe hanging on the right, as it travels past the drainpipe in the background. There is of course another line to the drainpipe. You can also see the signal line heading up northwest out of the web towards the little niche just below the rim at the top of the light (slightly obscured by some messy cobwebs). They all use those little niches as retreats. This spider had one of its slender little (though quite long relative to its body) legs visible sticking out of his retreat for about a day and a half earlier this week - it was rather cute. Edit: and again. It's near the signal line - silly me, of course it's for sensing the vibrations.

Pic 2 is of another one on the opposite side of the front door, that I took at the same time as the video last night. The web is in slightly better condition, though the light makes it very difficult to capture that, as well as to capture the signal line, but you can just make it out going up again northwest to the niche at the top of the light, where lurks this web's owner. You can't see it in this picture but there is another web behind, going from the other face of the wall round the corner, up to another niche on another face of the light. These little guys thrive here and it's a pleasure to have them arouned.

Edit: just took another pic of the web in 2 covering some of the light with my hand, with a better view of the signal line.

 

[Ah Lee]

Possible, perhaps even probable. Web spinning spider eyesight is a near complete mystery. With similar eye arrangements they range from near sighted bordering on blindness on out to 180 degree effective vision at a distance of several inches. The optical part of their brain also is often very small and unsophisticated. But they appear to incorporate their eyesight, 'intelligent' legs and the setae combined with a pretty sophisticated geometrical computational ability.
What does an average web spinner actually see? Shapes and shadows? Movement? Dark and light? Colors? A something registered in the brain produced by setae combined with some, most, or all of their eyes? What does a Lycosid see with it's 300+ degree field of vision? What do salticids see with the majority of their brain connected to their two main eyes?
The best possible move is to critically observe and learn. From brainiacs at the top of their fields on down to curious toddlers, the field seems to be wide open to new discoveries.

Movement I believe yes, but probably not very well. I used to feed Pepper just by throwing the dragonfly with my hand, but ever since she turned her web around to face me, she reacts very adversely to the swing of my arm, and perceives the landing of the dragonfly as an extension of my 'attack', running away from it. I now feed by using long tongs and flicking my wrist. Much less movement and I get a perfect feeding response everytime.

But I do believe their spatial awareness is much more acute than I initially thought.

I have about a dozen webs built in my room now by Stacey, Pepper and Xiaohua. It's a 3 x 2 metre room, and some of their webs get over a metre across. None of them have ever gotten in the way of regular human traffic.
Skittle has a web that extends the entire length of the tank. She rebuilds it every other day. She makes it bigger and bigger now, and very close to the swinging doors, but so far I have only had her web break due to me opening the doors once.
I have seen plenty of Nephila webs close to paths, but have personally never walked into one.

This makes me think they are aware of what their surroundings are, and possibly even short-term memory of possible animal traffic, which makes sense, because it would be a terrible waste of resources for a Nephila to build a web, only to have it destroyed by a passing boar.

One last interesting point, I had never had a golden web built in my room. A possibility might be diet, but even Xiaohua, who I caught as an adult with a golden web, built a plain-colored web in my room. That also makes me feel that the gold is a response to ambient light, or something else.

All of these is based strictly on my own observations and a lot of guesswork, so take it with a pinch of salt, but I try to learn as much as I can to hopefully be a better owner to them over time!

 

[Ah Lee]

Stumbled onto something interesting today. I found a colony of Nephilengys malabarensis, and out of the 8 webs I saw, all 8 were located in the same kind of setting: a vertical tree trunk with an overhang. With Skittles included, that means 9 out of 9 with webs in this very specific locations.

Here is an example.



This particular branch has 4 of these webs, every single one located in a nook so they can build a web like the one above.



This is really interesting to me because I wonder: how do these spiders find these specific locations? Do they spot it from afar and move towards it? This seems far-fetched because this would mean they would have really good eyesight, including perception of depth and distance.

Do they randomly walk around till they find the spot then? How do they know when they find it? Some of the webs are quite large so if not by sight, how did the spider determine the suitability of the spot? By memory of what it had walked past over the last few minutes?

This little field trip made me think that orbweb location may not be as random as I thought, but I really am interested to know how these little things are so spatially aware.

 

[The Snark]

Do they randomly walk around till they find the spot then? How do they know when they find it? Some of the webs are quite large so if not by sight, how did the spider determine the suitability of the spot? By memory of what it had walked past over the last few minutes?

Every time I see their webs I ask those questions.