Wikipedia:WikiProject Spiders/Unclear facts

Found anything on a spider page that sounds weird to you ("this 2mm long spider, the world's smallest invertebrate, hunts smaller invertebrates"), or want to know something on spiders that should be worked into an article("How long is the smallest spider?[1]")? Post it here.

Cribellate vs. ecribellate

Does anybody have a 'complete' list of a) cribellate vs. b) ecribellate species? which families only contain a) or b), which both, and if both, which inside the family? --Sarefo 22:23, 23 July 2006 (UTC)[reply]

Gliding spider

I could not find anything about Maratus volans actually using its flaps for gliding. This is mentioned on the Jumping spiders page. Does anybody have sources for this? --Sarefo 12:52, 24 July 2006 (UTC)[reply]

Ant mimicry

if somebody has has knowledge of ant-mimicking spiders, this is the place: Ant mimicry --Sarefo 22:37, 24 July 2006 (UTC)[reply]

Greek words

What does thela or thelon refer to (very probably Greek, in Heptathela, Hexathelidae and Mesothelae)? We (P0M and me) got so far as to determine it's probably from a word meaning 'nipple' or 'female'. --Sarefo 02:03, 27 July 2006 (UTC)[reply]

Mesothelae (meso- = middle) have their silk glands near the center of the body, while opisthothelae (opisth- = behind) have them at the end. so it very probably refers to silk spinnerets. --Sarefo 15:46, 14 October 2006 (UTC)[reply]

Taxon of Northern funnel-web spider

What taxon is Northern funnel-web spider?

There are a couple genera in Australia, can't remember the second one offhand, but I've seen discussions of which of the two is actually the more venomous, and it wasn't Atrax. I don't have time to root around for the reference right now, but I'm pretty sure it was on one of the Australian websites.P0M 20:32, 29 July 2006 (UTC)[reply]

Hadronyche, I think. Check out:

http://www.inchem.org/documents/pims/animal/atrax.htm
http://www.kingsnake.com/toxinology
http://www.emedicine.com/EMERG/topic548.htm
http://www.mja.com.au/public/issues/171_11_061299/harrington/harrington.html
http://www.usq.edu.au/spider/find/spiders/207.htm
http://www.spidy.goliathus.com/english/article-funnel-web-spider.php Says Hadronyche has the higher mortality rate.

I'm not sure which "northern funnel-web spider" was intended. Probably that article should be merged with the other article on Australian funnel-web spiders. P0M 07:08, 31 July 2006 (UTC)[reply]

Eating silk

The spider anatomy section says that spiders eat silk, which they do. is there a specialized mechanism for that, or do they just liquefy it like any other food? --Sarefo 15:48, 2 August 2006 (UTC)[reply]

They do not have to chew it. I have never read anything about the digestive process. I have observed web weaving spiders eating silk many times, typically as a spider goes back up a drop line she has just put down. I think jumpers do that too. The silk seems to me to go in almost as fast as it comes out. It's protein, and it contains the nutrients that the spider needs to make new silk, so I would guess that spiders have evolved to have the idea enzymes for breaking the protein bonds. I wonder whether anyone has ever calculated the total volume of silk produced by a spider to make a spiral web. Doing that job would give some idea of how compact the web fibers are. Human hair and diamonds are both largely carbon, but the density is vastly different even though we perceive hair to be a monofilament. P0M 17:10, 2 August 2006 (UTC)[reply]

Surprise, surprise. A visitor came to my living room today:

The Phidippus whitmani was a little reluctant to stay on my hand, so she descended on a drop line, and then after a while she changed her mind and moved back up toward my hand. So I had a good opportunity to watch her eating silk. Actually, she was moving her two front legs to fast to follow, but I could see her reach up with one claw, grab her drop line, pull herself up one notch, reach up with the other foot, grab hold, pull -- and in the process the silk disappeared. (I checked.) So the operation must be: grab the silk, pull it into your mouth, dispose of the loop you just made while you are reaching up and grabbing another loop to pull down. The process went very fast. She went up her dropline almost as fast as she descended on it. So imagine a kid given direct access to a cotton candy spinner. he reaches in with one hand, pulls a skein of cotton candy toward his mouth, reaches out grabs the far end of the skein he has just pulled toward his mouth... I don't know how one would go about investigating how the silk gets from the edge of the mouth on into the spider. Do they suck it in? Does something like peristalsis draw it in? Do they sort of stuff a gob in? The spider doesn't seem to need a napkin, so it looks like everything goes in straightaway as though there were a fishing reel on the inside pulling it all in as fast as it is delivered to the mouth. P0M 03:14, 5 August 2006 (UTC)[reply]

Has anyone seen anything published on this question? It's worth putting in an article, but we can't use personal research. P0M 03:37, 5 August 2006 (UTC)[reply]

Part of the orb-web creation is a temporary spiral that is eaten - see any account eg Google ["temporary spiral" viscid] or ["eat their previous web"] ---19S.137.93.171

IIRC they collect it as a white pellet, and consume it when the orb is finished.

(talk) 22:51, 30 June 2011 (UTC)[reply]

Hydraulic ?

I was going to add The Hydraulic Mechanism of the Spider Leg as a citation for the 'hydraulic' sentence in Spider.

"Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by hydraulic pressure."

but that is somewhat contradicted by the paper

"the anatomical form of the joint rarely permits the presence of antagonistic extensors (see Manton, 19580,%. 151 for an exception)"

Maybe some spiders have extensors and some other arthropods lack them ?
'Rarely' and 'most' may weasel out of it ?
I would have thought hydraulics were common in insects ?

"... locomotion of Diptera and Lepidoptera larvae are due to a hydraulic mechanism (Caillere,. '72; Parry and Brown, '59a,b)"

Needs clarification - I'm too ignorant !

---19S.137.93.171 (talk) 23:12, 30 June 2011 (UTC) Instead of clarifying we can be ambiguous. "Spiders have only flexor muscles in their limbs and extend them by hydraulic pressure."[reply]

Crevice_weaver

On the crevice weaver (Filistatidae) page there's a confusing, unsourced statement that I can't correct as I don't know what it's meant to read as if anyone can help.

"A striking visual characteristic of the family, beside dimorphism, is the unusual upward bend encountered near the femur of the first pair of legs. While resembling hydraulic muscle mechanisms akin to arthropods[...]"

As spiders are arthropods, I'm a bit confused as to what is meant by this, so if anyone knows what it should be referring to could they look into it? Hedge89 (talk) 16:48, 20 January 2016 (UTC)[reply]

@Hedge89: I agree that as written it doesn't make sense. None of the references in the article contain that information as far as I can see and Ramírez (2014) has detailed information about morphology. Searching via Google just shows that the Wikipedia article has been copied all over the place.

The image of Kukulcania hibernalis here doesn't show any obvious difference between legs I and II.

The best I can do for now is to tag as needing citation; if none turns up, the information should be removed. Peter coxhead (talk) 15:56, 21 January 2016 (UTC)[reply]

@Peter coxhead: Thanks for that, I wasn't really sure of the procedure for dealing with summat like that. Hedge89 (talk) 17:45, 21 January 2016 (UTC)[reply]

@Hedge89: whenever you think that unsourced statements are doubtful, don't hesitate to put {{citation needed}} after them. Peter coxhead (talk) 20:24, 21 January 2016 (UTC)[reply]