St Andrew's Cross Spider

[John53]

This mornings garden bug is a St Andrews Cross Spider. Named because of the bands of silk that form a shape similar to the cross St Andrew was reportedly crucified on. Biologists have several ideas on the purpose of the cross... to stabilise the web, camouflage from predators or to attract prey. Apparently it reflects UV light which might attract insects. It was 6.30am when I took the photo so the rest of the web can't be seen because there's no sunlight reflecting off it. I'll try again later to see if I can get it with the rest of the web visible.

Apologies for my dirty fence.

 

[Valjean]

Cute.

 

[exchemist]

This mornings garden bug is a St Andrews Cross Spider. Named because of the bands of silk that form a shape similar to the cross St Andrew was reportedly crucified on. Biologists have several ideas on the purpose of the cross... to stabilise the web, camouflage from predators or to attract prey. Apparently it reflects UV light which might attract insects. It was 6.30am when I took the photo so the rest of the web can't be seen because there's no sunlight reflecting off it. I'll try again later to see if I can get it with the rest of the web visible.

Apologies for my dirty fence.

View attachment 69392

Interesting but I'd like to understand what we are looking at. Is the blue cross just a visible part of the web, then? Why are the lines so thick, when spider's silk is so fine?

 

[John53]

Interesting but I'd like to understand what we are looking at. Is the blue cross just a visible part of the web, then? Why are the lines so thick, when spider's silk is so fine?

It's a web decoration or stabilimenta. The rest of the web is like a usual orb weaver type construction, it's not visible in my photo, I'm guessing lack of light meant the sensor couldn't pick it up.

Stabilimentum - Wikipedia

 

[John53]

This is about the best I can get of the web, the sun doesn't really hit the spot it has built it.

 

[Dan From Smithville]

Awesome! What a beautiful orb weaver and an interesting web too.

 

[John53]

And a small butterfly, there's hundreds of them in the yard at the moment, they're only about 10mm. I think they're a type of Leptotes plinius but I don't know for sure.

ETA: I'm probably wrong about the name unless there is only males in my yard, the females look completely different. There's a heap of small grey butterflies that it could be.

 

[John53]

Awesome! What a beautiful orb weaver and an interesting web too.

I really need to pressure wash the fence.

 

[Dan From Smithville]

And a small butterfly, there's hundreds of them in the yard at the moment, they're only about 10mm. I think they're a type of Leptotes plinius but I don't know for sure.

View attachment 69400

I'm only marginally good at picture keying local species. Anything outside of Missouri needs to be pretty well-known for me to get it.

Edit: Butterflies and moths I mean.

 

[Dan From Smithville]

I really need to pressure wash the fence.

After the spider has moved on I hope. But don't let me pressure you.

 

[John53]

I'm only marginally good at picture keying local species. Anything outside of Missouri needs to be pretty well-known for me to get it.

Edit: Butterflies and moths I mean.

I'm 99.9% sure I'm wrong. It looks like a male Leptotes plinius but the females of those look completely different and I doubt if I have a yard full of males. I've found 6 that it could be but they all look the same to me.

 

[John53]

After the spider has moved on I hope. But don't let me pressure you.

It would require digging out the pressure washer, finding a long enough lead to reach the fences and considerable effort to do the actual pressure washing so it's unlikely to happen.

 

[Dan From Smithville]

I'm 99.9% sure I'm wrong. It looks like a male Leptotes plinius but the females of those look completely different and I doubt if I have a yard full of males. I've found 6 that it could be but they all look the same to me.

Some of our smaller species all look very much alike to me. They don't make matters easy for me by staying still for a while either.

 

[Dan From Smithville]

It would require digging out the pressure washer, finding a long enough lead to reach the fences and considerable effort to do the actual pressure washing so it's unlikely to happen.

Technical issues have saved me a lot of trouble in the past too.