# What insect made this, and why? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 7, 2013, 1:59am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223 "2013-09-07T01:59:48Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [January 31, 2014, 3:59pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/101 "2014-01-31T15:59:40Z")
> [@Snowboarder\_Bo](#): > > Dear Og its a Chtorr! I hope we don’t get any sugar storms … ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [January 31, 2014, 7:13pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/102 "2014-01-31T19:13:01Z")
Looks like a little insect concentration camp. ---
**Author:** ![Rich\_Mann](https://avatars.discourse-cdn.com/v4/letter/r/ce73a5/32.png) [@Rich\_Mann](https://boards.straightdope.com/u/Rich_Mann)\ **Post date:** [February 2, 2014, 10:36am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/103 "2014-02-02T10:36:27Z")
> [@Morgyn](#): > > [Updates](http://www.wired.com/wiredscience/2013/12/mysterious-structures-amazon/)! They still don’t know what kind of spider it is, but there’s tons of speculation along with confirmed sightings in multiple other countries. The spiderling in the video at the top of the linked page appears to be repairing its nest. It is using its hindmost legs in the way that they do. You can clearly see the silk for just a moment at about the 1:56 mark. I wonder how long they live in the little house Mommy made them. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [February 2, 2014, 10:50pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/104 "2014-02-02T22:50:00Z")
Since we’ve discovered it is a spider egg hatchery, I thought it would be interesting to discuss the engineering of the structure. First, look at the “fence”. It is a ring structure that appears to be made totally of spidersilk. Each of those fenceposts is a dense wrapping of spidersilk. It is hard to tell how stiff they are, even watching that video, but the slight outward bend suggests that the crosslinks are not just the barrier, but are also support structures. The posts are all tied together and form a mutually supporting structure. Then there is the tower. The base is a wide cone, which provides stability, but appears overly large for just that purpose, so naturally it makes sense that it is the egg protector. The spire then rises above as another tall column of spidersilk. What is interesting is that the spire is surrounded by a network of guywires to anchor and support the structure. Very interesting. I wonder at the purpose of the spire, which hasn’t really been demonstrated. Is it a launch point for the baby spiders to the world? Why make such a tall spire to cover the egg? It doesn’t serve any purpose in that manner. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 3, 2014, 3:08pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/105 "2014-02-03T15:08:07Z")
The bit that I just can’t get my mind past is that it houses only one egg. This is a K-selected arthropod-- I wouldn’t have guessed that there were _any_ of those. Putting this into perspective, this means that these spiders must make these structures multiple times in their lives, probably many times, certainly more than twice on average. No combination of numbers seems to make sense: If, for instance, each female spider that reaches maturity makes 20 of these in her lifetime, that means that over 10% of the spiderlings reach maturity. How on Earth can they manage that? What kind of defense against being eaten are they packing? ---
**Author:** ![Gedd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gedd/32/4938_2.png) [@Gedd](https://boards.straightdope.com/u/Gedd)\ **Post date:** [February 3, 2014, 6:24pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/106 "2014-02-03T18:24:00Z")
> [@Irishman](#): > > Since we’ve discovered it is a spider egg hatchery, I thought it would be interesting to discuss the engineering of the structure. > > First, look at the “fence”. It is a ring structure that appears to be made totally of spidersilk. Each of those fenceposts is a dense wrapping of spidersilk. It is hard to tell how stiff they are, even watching that video, but the slight outward bend suggests that the crosslinks are not just the barrier, but are also support structures. The posts are all tied together and form a mutually supporting structure. > > Then there is the tower. The base is a wide cone, which provides stability, but appears overly large for just that purpose, so naturally it makes sense that it is the egg protector. The spire then rises above as another tall column of spidersilk. What is interesting is that the spire is surrounded by a network of guywires to anchor and support the structure. > > Very interesting. I wonder at the purpose of the spire, which hasn’t really been demonstrated. Is it a launch point for the baby spiders to the world? Why make such a tall spire to cover the egg? It doesn’t serve any purpose in that manner. Once again we are reminded that humans aren’t as special as we think we are. ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [February 3, 2014, 6:42pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/107 "2014-02-03T18:42:30Z")
> [@Chronos](#): > > The bit that I just can’t get my mind past is that it houses only one egg. This is a K-selected arthropod-- I wouldn’t have guessed that there were _any_ of those. Putting this into perspective, this means that these spiders must make these structures multiple times in their lives, probably many times, certainly more than twice on average. No combination of numbers seems to make sense: If, for instance, each female spider that reaches maturity makes 20 of these in her lifetime, that means that over 10% of the spiderlings reach maturity. How on Earth can they manage that? What kind of defense against being eaten are they packing? One speculation I read is that they prey mainly on ants, and the nests are placed in ant-heavy areas. It’s possible that the ants themselves keep most other potential threats away, and the fence keeps the ants away until the spiderlings are big enough to go hunting. I would venture a guess that part of the purpose of the structure is camouflage of sorts. It bears a certain resemblance to a patch of fungus with a fruiting body–not something a predator large enough to ignore the ants would have an interest in. ---
**Author:** ![Morgyn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/morgyn/32/3041_2.png) [@Morgyn](https://boards.straightdope.com/u/Morgyn)\ **Post date:** [February 4, 2014, 3:09am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/108 "2014-02-04T03:09:20Z")
Looks like Phil and crew may have discovered a second spider species while they were out there looking at the constructor spider. This one they’re referring to as a [decoy spider](http://blog.perunature.com/2012/12/new-species-of-decoy-spider-likely.html). ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [February 4, 2014, 7:33am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/109 "2014-02-04T07:33:04Z")
> [@Chronos](#): > > The bit that I just can’t get my mind past is that it houses only one egg. This is a K-selected arthropod– S-plain? > [@](#): > > I wouldn’t have guessed that there were _any_ of those. Putting this into perspective, this means that these spiders must make these structures multiple times in their lives, probably many times, certainly more than twice on average. No combination of numbers seems to make sense: If, for instance, each female spider that reaches maturity makes 20 of these in her lifetime, that means that over 10% of the spiderlings reach maturity. How on Earth can they manage that? What kind of defense against being eaten are they packing? How complex are those structures compared to webs? Spiders make dozens of webs in their lifetimes, don’t they? Yes, the normal reproductive strategy for spiders is to make an eggsack full of a million eggs and let numbers dominate, and there’s no way they’re making a million of those, but surely a couple dozen is not outrageous. The trickier element is that many spiders die after reproducing. That would be a lousy strategy here. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [February 4, 2014, 3:56pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/110 "2014-02-04T15:56:37Z")
> [@Irishman](#): > > S-plain? [A bit of jargon from ecological theory.](http://en.wikipedia.org/wiki/R/K_selection_theory) K-selected species are selected for long life span and tend to have few but high-quality offspring. r-selected species are selected for maximum reproductive rate, and tend to have very large numbers of that individually have low survival. Humans and elephants are K-selected. Most small animals like arthropods are s-selected. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 4, 2014, 4:50pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/111 "2014-02-04T16:50:38Z")
> [@](#): > > Most small animals like arthropods are s-selected. Typo: You meant to say “r” there. ---
**Author:** ![GargoyleWB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gargoylewb/32/199_2.png) [@GargoyleWB](https://boards.straightdope.com/u/GargoyleWB)\ **Post date:** [February 4, 2014, 8:10pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/112 "2014-02-04T20:10:00Z")
> [@Balance](#): > > …and the fence keeps the ants away until the spiderlings are big enough to go hunting… How would this fence appear to touchy-feelery type bugs? Perhaps it is indeed something that seems to be an impenetrable untasty barrier to predators? I know that if I’m stumbling around in my dark basement and my hands feel some strange stretchy unyielding barrier in front of me, I get the hell out of there and ask my wife to go get her own damned socks. ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [February 4, 2014, 10:00pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/113 "2014-02-04T22:00:17Z")
> [@GargoyleWB](#): > > How would this fence appear to touchy-feelery type bugs? Perhaps it is indeed something that seems to be an impenetrable untasty barrier to predators? I know that if I’m stumbling around in my dark basement and my hands feel some strange stretchy unyielding barrier in front of me, I get the hell out of there and ask my wife to go get her own damned socks. If I had to guess, I’d say it probably registers as just a wall of junk to go around–maybe something like an inedible lichen or bit of tree bark. It’s conceivable that it somehow mimics something dangerous (to tiny bugs) in the area, but I have no idea what. The article **Morgyn** linked above mentioned that the team observed a large ant going out of its way to avoid the fence, but one observation is not much to go on. Fun thought: what if the spire looks like a cordyceps fruiting body to ants? “Oh, shit, Raccoon City dead ahead–veer off!” (It doesn’t actually look like one, I don’t think, but I’m not an ant. Just easily amused.) ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [February 4, 2014, 10:00pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/114 "2014-02-04T22:00:33Z")
I think the whole interrelationship is interesting. We have fairly specific ants & trees in a symbiotic relationship and a spider living specifically off that relationship. Throw in mites, infesting the ant colonies I imagine, and possibly a primary food source for baby spiders. ---
**Author:** ![Morgyn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/morgyn/32/3041_2.png) [@Morgyn](https://boards.straightdope.com/u/Morgyn)\ **Post date:** [July 2, 2014, 2:55am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/115 "2014-07-02T02:55:30Z")
I’m bumping this thread because, despite googling and news alerts, I’ve yet to see an update. It’s been more than 5 months since those little spiderlings hatched. They have to have grown up and been identified by now! C’mon, \*\*Colibri \*\*and **mozchron** , what’s the news? ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [July 2, 2014, 5:19am UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/116 "2014-07-02T05:19:10Z")
There seem to be some huge gaps of information that the writer of the original article didn’t even wonder about. Like, what kinds of materials are used? Are the fence posts rigid, or flexible? What’s inside the dome if it is broken open? How are the fencepost attached to the base surface? Is the geometry exact? Did anybody look at any parts of it under magnification? I can’t believe the experts they asked didn’t even express an interest in finding out such details, but just said “Looks like it might be a \_\_\_ , to me”. (I didn’t read in detail all responses, so if that is in there, somebody can update the thread.) ---
**Author:** ![Morgyn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/morgyn/32/3041_2.png) [@Morgyn](https://boards.straightdope.com/u/Morgyn)\ **Post date:** [July 2, 2014, 4:34pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/117 "2014-07-02T16:34:13Z")
> [@jtur88](#): > > There seem to be some huge gaps of information that the writer of the original article didn’t even wonder about. Like, what kinds of materials are used? Are the fence posts rigid, or flexible? What’s inside the dome if it is broken open? How are the fencepost attached to the base surface? Is the geometry exact? Did anybody look at any parts of it under magnification? I can’t believe the experts they asked didn’t even express an interest in finding out such details, but just said “Looks like it might be a \_\_\_ , to me”. > > (I didn’t read in detail all responses, so if that is in there, somebody can update the thread.) Other articles linked above will tell you that it’s spider silk, that the cone contains a single egg at the base, and no one knows more than that. They also mounted a special expedition to find more samples of the structure, so they’re all pretty interested. ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [December 15, 2016, 2:05pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/118 "2016-12-15T14:05:30Z")
> [@mozchron](#): > > OK, > > After sending this to lots of colleagues (many of whom actually received this from multiple sources), the consensus seems to be… > > …possibly the egg sac of some kind of [cribellate spider](http://en.wikipedia.org/wiki/Cribellum). These spiders have a unique type of silk spinning apparatus that allow them to create the kind of silk strands shown in some of the closeup photos. And some do make elaborate protected or stalked egg sacs. > > So we in the entomological community still don’t know for certain, but this seems (at the moment) the most likely bet. Hopefully the scientist who found it will try to see what comes out of it. > > [Here’s an article with details.](http://bugtracks.wordpress.com/2013/09/09/cribellate-spiders-and-some-more-thoughts-on-that-mysterious-thing-from-peru/) BUMPING FOR UPDATE [Yes, seems to be a new species of cribellate spider.](http://www.youtube.com/watch?v=Unc-g9AHl2Y&feature=youtu.be) ---
**Author:** ![iiandyiiii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/iiandyiiii/32/7924_2.png) [@iiandyiiii](https://boards.straightdope.com/u/iiandyiiii)\ **Post date:** [December 15, 2016, 2:42pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/119 "2016-12-15T14:42:46Z")
Is there a species name? ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [December 15, 2016, 4:58pm UTC](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223/120 "2016-12-15T16:58:20Z")
> [@iiandyiiii](#): > > Is there a species name? No, not yet. That takes a while. [Previous page](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223.md?page=5) [Next page](https://boards.straightdope.com/t/what-insect-made-this-and-why/668223.md?page=7)