What's that white stuff? (Spider)

[cfcRebel]

Or what is it for? I thought the idea is to make the web as invisible as possible so that insects don't see it and fall into it. Strange....

C/C welcome.

[Leorooster]

Nice shot. The visible part is to advertise the presence of the web to birds allowing them to avoid the web, since these spiders are smart enought (I believe) that they can't catch a bird...hehe.

[montreal]

Is that true Leorooster??? How smart of the spiders...

[Dandaman_24]

Its not only for birds to see, i believe its for humans to see aswell, as we always walk into their webs.

[Leorooster]

Yes, in the past, some believed that the white stuff was used to strengthen the web, but experiments have been done to prove that it's used to avoid birds and other large predators.

[cfcRebel]

Wow, they are really smart! :D Thanks leorooster.
The zigzag pattern is really something. Maybe the spider should paint it red. ;)

[tupe]

Good-looking spider pic and an interesting biology lesson all in one. Thanks!

[Leorooster]

Wow, they are really smart! :D Thanks leorooster.
The zigzag pattern is really something. Maybe the spider should paint it red. ;)

Well maybe we, human-being, should paint it for them as we are believed to be the smartest in the known world;) ;) :p :p

[cfcRebel]

Good-looking spider pic and an interesting biology lesson all in one. Thanks!Thanks tupe. :)

[montreal]

Very interesting indeed.

Next the spiders are gonna spell out "mind the web" :D

[Dweezil]

...and here all along, Ialways thought that the zigzag pattern was their antenna to the mother ship. Boy, is my face red. :o

[cfcRebel]

LOL! :D Thanks for looking.

[GTogs]

Great Shot! One thing about this forum is the opportunity to see so many unique photos!

[Leorooster]

Great Shot! One thing about this forum is the opportunity to see so many unique photos!

........and learn at the same time too......

[Bald Eagle]

Very neat shot, and a great lesson as well. I wonder if that would work for kids as well?

[herderdog]

Too cool!:cool: I like it!

[jfrancho]

Next the spiders are gonna spell out "mind the web" :D"Some Pig"

[Maureen Souza]

"Some Pig"

:lol: :lol: :lol: Definately a favorite book of mine.

Great picture and wonderful arachnoid lesson. This forum is just the best learning tool.

[Drk Orange]

A similar spider here in Australia makes an X shape in its web. I have one out the back yard, I'll be back in a sec...

[Drk Orange]

Here we go:

They don't always build the X, and this new one has only built half of it.

http://i17.photobucket.com/albums/b60/Dark_Orange/Arachnids/Cross.jpg



I took a snap of this one's mother last year who managed the whole thing:

http://members.iinet.net.au/~miketz/sssf/StAndrewsCross_a.jpg

[Maureen Souza]

Here we go:

They don't always build the X, and this new one has only built half of it.

http://i17.photobucket.com/albums/b60/Dark_Orange/Arachnids/Cross.jpg



I took a snap of this one's mother last year who managed the whole thing:

http://members.iinet.net.au/~miketz/sssf/StAndrewsCross_a.jpg

Way too cool. Nice shots as well.

[Drk Orange]

Way too cool. Nice shots as well.

Thanks. I took plenty of her when I was learning to use the 300D. Here's one of my faves:

http://members.iinet.net.au/~miketz/sssf/StAndrewsCross070604b.jpg

It looks nice uncompressed, I'd like to try for another like it now that I have L glass. ;)

[chemicalbro]

Very cool shot.... you'de think tho that spiders wouldn't want to advertise their presence to birds............ I'd rather get a broken web than be eaten........ I guess they are pretty smart tho coz i seen a thing on discovery a few weeks back and this woman was doing experiments and popping flies in the same part of the web each day.......... each day the spider wouldbuild its new web and strengthen that part of the web and the hub (centre) of the web would move towards the prime capture area..... they are also the most numerous predator on earth so they gotta be doing something right ;)

[Maureen Souza]

Wow...that last post of the web is amazing. I tried some in my garden yesterday morning but there wasn't enough sunlight to really show off the web like that. Very awesome work!

[RockOne]

Nice spider shots !.
We get the occasional St Andres Cross around here. The white zig-zag pattern on the web, called the stabilimentum, is used to reflect UV light from the web. Insects that are attracted to flowers because of the UV pattern of flowers are 'tricked' into thinking that the web is a flower, and then the trap is sprung...:-). The rest of the web is a poor reflector of UV light.

[Leorooster]

Here we go:

They don't always build the X, and this new one has only built half of it.

http://i17.photobucket.com/albums/b60/Dark_Orange/Arachnids/Cross.jpg



I took a snap of this one's mother last year who managed the whole thing:

http://members.iinet.net.au/~miketz/sssf/StAndrewsCross_a.jpg

Oh man, that's a STOP sign......;) ;) Nice pics.

[Leorooster]

Both Steve and Chemical are correct, the stabilimentum is multi-functional. Check this out:

http://www.bugsinthenews.com/stabilimentum_and_some_notions_on%20function.htm

[cfcRebel]

Wow, nice captures Drk_Orange. I think mine and yours are relatives - quite a lot of similarities except the shape of the abdomen.
It's funny that, even spiders have international "road signs". The ones in the US use straight vertical zigzag line, and the downunder's use X. And its legs even folded inline with the X. :shock: That is so COOL! Thanks for sharing.

[cfcRebel]

Nice spider shots !.
We get the occasional St Andres Cross around here. The white zig-zag pattern on the web, called the stabilimentum, is used to reflect UV light from the web. Insects that are attracted to flowers because of the UV pattern of flowers are 'tricked' into thinking that the web is a flower, and then the trap is sprung...:-). The rest of the web is a poor reflector of UV light.

Thanks for the information RockOne. Multi-functional sign, it sure is interesting. ;)

[RockOne]

cfcRebel, there are many different patterns of stabilimentum, disks, sprials and cross-shaped ones, with varying numbers of elements. All of the St Andrews cross spiders I have seen have the diagonal cross though.
Re the bird theory - not sure how it applies to the St. Andrews cross, in my experience the webs are very close to the ground in vegetation, where you would not find a lot of flying birds. Although other orb-weaving type spiders can build big webs in between trees, where there is a real danger of 'birdstrike' and they do not build stabilimenta. Guess its just one of lifes little mysteries at the moment.

[cfcRebel]

You are right Steve. I saw two of them. One built its web at about waist level. The other one built slightly higher than top of my head. They both have a straight-line stabilimentum. The higher one was bigger(web & the spider), the web diameter is approx. 1 meter, maybe even wider than that. :)

[Drk Orange]

Thanks for the information RockOne. Multi-functional sign, it sure is interesting. ;)

Multi-function allright - "Birds, keep clear. Insects, come on in"


And another of the lady, without any cross at all.

http://members.iinet.net.au/~miketz/sssf/St_Andrews_Cross_180704a.jpg

[spiders]

That is called a stabilimentum. there are at least a dozen scientific papers published about the particular function of it. Alerting birds to its presence is ONE. Others include flower mimicry, simulating open areas (where flying insects normally go) to attract bees and other pollinators. It also renders the spider cryptic-especially juvenile spiders that build disc-shaped ones. Most Argiope species build the "Z" shaped stabilimenta, but other species have other forms. There are also population-level differences in stabilimentum shapes. It gets its name from its original hypothesized function--to stabilize the web. Ironically, this is the LEAST likely function for it.

[desheeke]

The spiders that make the zig-zag pattern are referred to as the alphabet spiders, since they look like Z's and are from the species argiope, they're all over in more humid places. It's still unclear what the zig-zag is for, if you ever watch them bounce in the web when you blow on them you can no longer really see the zig-zag, so if I had to make a guess it's there to attract the pray.