"Tarantulas eject silk from feet"

[Draiman]

http://www.bbc.co.uk/nature/13382903

I don't believe it.

 

[Hobo]

Interesting!

Also,

This is where Dr Rind's own pet Mexican flame knee tarantula, named Fluffy, came into the study.

Did Joe have a part in this?

 

[BrynWilliams]

I have just glanced through the paper itself, have you read it?

Although their 'n' was small, only 8 cases for the G rosea, their methods seem pretty reasonable. They observed the specimen walking on microscope slides, turned the plate vertically, shook the plate mechanically until a tarsal slip was seen, then examined the footprint.

Positions of feet were recorded throughout and any slides that the spinarrettes came into contact with were recorded and excluded.

It's interesting that silk strands were seen post slippage in an area matching the footprint and not surrounding it at all .

I believe I can't post a link for the paper, copyright etc, but if anyone would like it, its on the bjem website for those with academic access . Either that or pm me

 

[jondee84]

What is there not to believe? Its a scientific experiment.

 

[Rabid538]

It seems that A. seemanni lacks spigots. Although, I would like to see the same experiment done (sealing the spinnerets) on other species like G. rosea to see if the results differ. I wish the whole article was available, not just the abstract.

http://www.ncbi.nlm.nih.gov/pubmed/19847209
http://www.ncbi.nlm.nih.gov/pubmed/21562174
http://faculty.washington.edu/fishg...DFs/2009-spider-silk-feet-tarantula-reply.pdf

---------- Post added at 10:05 AM ---------- Previous post was at 08:59 AM ----------

What is there not to believe? Its a scientific experiment.

You need more than just one experiment to claim it as true. A lot more research has to be done and it has to be tested on more species.

It is very interesting though and I hope they can find a connection between which species have spigots and which lack it. You would think it would be more developed on arboreal species.

 

[esotericman]

The 2006 paper with A. seemani was refuted shortly after, this paper uses several species. Here is the summary to save some surfing:

Rind, C., et al. Tarantulas cling to smooth vertical surfaces by secreting silk from their feet. Journal of Experimental Biology 214, 1874-1879.

Like all spiders, tarantulas (family Theraphosidae) synthesize silk in specialized glands and extrude it from spinnerets on their abdomen. In one species of large tarantula, Aphonopelma seemanni, it has been suggested that silk can also be secreted from the tarsi but this claim was later refuted. We provide evidence of silk secretion directly from spigots (nozzles) on the tarsi of three distantly related tarantula species: the Chilean rose, Grammostola rosea; the Indian ornamental, Poecilotheria regalis; and the Mexican flame knee, Brachypelma auratum, suggesting tarsal silk secretion is widespread among tarantulas. We demonstrate that multiple strands of silk are produced as a footprint when the spider begins to slip down a smooth vertical surface. The nozzle-like setae on the tarsi responsible for silk deposition have shanks reinforced by cuticular thickenings, which serve to prevent the shanks' internal collapse while still maintaining their flexibility. This is important as the spigots occur on the ventral surface of the tarsus, projecting beyond the finely divided setae of the dry attachment pads. We also reveal the structure and disposition of the silk-secreting spigots on the abdominal spinnerets of the three tarantula species and find they are very similar to those from the earliest known proto-spider spinneret from the Devonian period, giving another indication that silk secretion in tarantulas is close to the ancestral condition.

 

[Rabid538]

The 2006 paper with A. seemani was refuted shortly after, this paper uses several species. Here is the summary to save some surfing:

Rind, C., et al. Tarantulas cling to smooth vertical surfaces by secreting silk from their feet. Journal of Experimental Biology 214, 1874-1879.

Like all spiders, tarantulas (family Theraphosidae) synthesize silk in specialized glands and extrude it from spinnerets on their abdomen. In one species of large tarantula, Aphonopelma seemanni, it has been suggested that silk can also be secreted from the tarsi but this claim was later refuted. We provide evidence of silk secretion directly from spigots (nozzles) on the tarsi of three distantly related tarantula species: the Chilean rose, Grammostola rosea; the Indian ornamental, Poecilotheria regalis; and the Mexican flame knee, Brachypelma auratum, suggesting tarsal silk secretion is widespread among tarantulas. We demonstrate that multiple strands of silk are produced as a footprint when the spider begins to slip down a smooth vertical surface. The nozzle-like setae on the tarsi responsible for silk deposition have shanks reinforced by cuticular thickenings, which serve to prevent the shanks' internal collapse while still maintaining their flexibility. This is important as the spigots occur on the ventral surface of the tarsus, projecting beyond the finely divided setae of the dry attachment pads. We also reveal the structure and disposition of the silk-secreting spigots on the abdominal spinnerets of the three tarantula species and find they are very similar to those from the earliest known proto-spider spinneret from the Devonian period, giving another indication that silk secretion in tarantulas is close to the ancestral condition.

That is the second link I posted.

 

[AphonopelmaTX]

I'll support the tarsi silk production idea when someone finds the silk glands responsible for it.

 

[esotericman]

I'll support the tarsi silk production idea when someone finds the silk glands responsible for it.

TEM of tarsal setae would be a bit tough to pull off, and also finding anyone who can actually do histology at that level, ouch. Although cryo-TEM would greatly simplify the process, identifying the glads would still be difficult. I don't know of anyone working on this in theraphosids. Most of the current buzz is from material engineers who have kicked the tires and more people are actually looking.

I've been pondering repeating this experiment with some of my spiders, I mean it's pretty simple to take a tarantula and run it onto a slide and see if there is any webbing left behind, if they slip. I'll have a better idea once I lay hands on the original paper with mats and methods.

And yes, I know the link was the same, I posted the summary to save some clicking, as many folks cruise the boards via phones.

 

[Rabid538]

TEM of tarsal setae would be a bit tough to pull off, and also finding anyone who can actually do histology at that level, ouch. Although cryo-TEM would greatly simplify the process, identifying the glads would still be difficult. I don't know of anyone working on this in theraphosids. Most of the current buzz is from material engineers who have kicked the tires and more people are actually looking.

I've been pondering repeating this experiment with some of my spiders, I mean it's pretty simple to take a tarantula and run it onto a slide and see if there is any webbing left behind, if they slip. I'll have a better idea once I lay hands on the original paper with mats and methods.

And yes, I know the link was the same, I posted the summary to save some clicking, as many folks cruise the boards via phones.

Oh, okay. Sorry about that!
That would be really cool if you repeated the experiment. Do you think it would be possible for you to send me the whole article if you find it?

 

[desertanimal]

Do you think it would be possible for you to send me the whole article if you find it?

PM me your email address and I'll send it to you.

 

[ArachnoYak]

Check this out:

Tarantulas excreting silk from unusual places

http://news.nationalgeographic.com/news/2011/05/110516-spiders-tarantulas-webs-spider-man-science-animals/?source=link_fb20110516tarantulasshootsilk

 

[Nerfaphytum]

Great find!!!!!! Thanks Boo!, it just goes to show our limited physical understanding of these beautiful creatures.

 

[Shea]

Wow, what a great read! I never would have thought

 

[AphonopelmaTX]

I'll support the tarsi silk production idea when someone finds the silk glands responsible for it.

I take this back now that I've read the article at the National Geographic site. I can't wait to read the research finding in the Journal of Experimental Biology when it is published.

 

[Kirk]

I have a pdf of the Journal of Experimental Biology paper. Send me your email address via PM and I'll pass it along.

 

[esotericman]

Kirk,

You know SEM at all?

I took some quick shots from C. cyanopubescens and the setae look very similar to the P. regalis in Fig. 4 A. I'll try to upload them soon, sadly I'm off work the next couple of days and forgot them on the server.

The main problem I was having was charging, but the sample has gone into a 48C oven and I'll sputter coat again and peak next week. I could not see any setae with pores.

 

[Kirk]

Kirk,

You know SEM at all?

I took some quick shots from C. cyanopubescens and the setae look very similar to the P. regalis in Fig. 4 A. I'll try to upload them soon, sadly I'm off work the next couple of days and forgot them on the server.

The main problem I was having was charging, but the sample has gone into a 48C oven and I'll sputter coat again and peak next week. I could not see any setae with pores.

Yes, I'm quite proficient with SEM. In addition to several rounds of sputter coating (or increasing coating time), it's useful to tilt the stub platform in the coater, to ensure better coverage. Also, you might need to add some silver paint to the base of the leg to ensure better grounding. The shorter the specimen the better, if it's directed away from the stub.

 

[Ariel]

Tarantula's spinning webs from their feet?

So, I'm a fan of Science Now on Facebook and this particular article was posted today:

http://news.sciencemag.org/sciencenow/2011/05/scienceshot-spiders-silk-slipper.html?ref=hp

 

[LirvA]

Yeah pretty cool. Also it should be pretty obvious if you think about it. Only natural imo.