Spiders

[Huntn]

We get orb weavers here. They are beautiful.

We have those too, pretty webs!

A post somewhere else from 7 years ago:
We have a Spiny Orb Weaver that has taken up residence above our front foundation shrubs (in Texas). Not only is the web large, I'm amazed that it extends up to a tree, about 7' above. Fortunately this web is out of the way and in a perfect location to catch plentiful stealth mosquitos. How does it evaluate a good spot for building? How good does it see for such evaluation? Does this mean it had to climb that tree and descend down?

Mostly I'm impressed with the precision this web is being constructed. The radials are all precise. It (gender unknown) cycles around the radial threads, pulls the radial up to attach the cross thread it's currently laying, then moves to the next radial. I tried to take a picture, but it was too small and the thread too fine to be seen by my iPhone.

I also wonder how spiders exist around the world that have this web building in their DNA. Are they all of common descent, (how did they spread?) or did they develop this talent independently?

 

[lizkat]

For fans of a good sized but harmless spider, good news, the Joro's probably coming your way.

Palm-size invasive spiders could eventually colonize East Coast, including Boston - The Boston Globe

The joro spider, native to Japan, is spreading throughout the southeastern United States, though it isn’t dangerous or aggressive to humans. By one expert’s estimate, it would take 5-10 years for the spider to make its way to New England.

www.bostonglobe.com

The joro spider first arrived in the US around 2013, most likely as stowaways on shipping containers. According to the study, the joro spider only needs a narrow period of suitable weather to complete its lifecycle.

“The species simply needs to have a 3-4 month window of time in the summer and fall to carry out its life cycle, and then lay eggs before dying. Then, the egg sacs need to survive the winter,” he said. “But, based on the range of this species in its native land (east Asia), Boston is pretty similar.”

The study also found that the joro spider can function in a cold environment better than the golden silk spider, which is a closely related species.

Davis said female joro spiders can be about 3 to 4 inches long with their legs outstretched. Their abdomen is about the size of a grape, he said. Male joro spiders are much smaller.

“The males are just little guys — only about 1-2 [centimeters] in size,” he said.

They look like this... pretty jazzy addition to any garden!

​

 

[Chew Toy McCoy]

Starts with my fav, the jumping spider, but then shows my new fav to me spider, the velvet. Don't seem to be available on the US market much though.

 

[Yoused]

How does it evaluate a good spot for building? How good does it see for such evaluation? Does this mean it had to climb that tree and descend down?

It is my understanding that, the silk being very fine and light, the spider spins out a strand and lets the end float up until it makes contact with an anchor point, then sticks the near end to a nearby anchor and sets up more radials off the first line. I believe the radials are the dry lines, upon which she navigates, and the spirals are the stickies.

As far as vision, spiders have two or three sets of eyes, of differing optical profile. There are usually two telephotos for seeing what is way over there and clusters of shorter range eyes. There may also be other, wide view, eyes intended for predator evasion. The telephotos are cylindrical, which is one reason for all the legs, so that the spider can rapidly move around to the best viewing angle. Owls have cylindrical eyes as well, which is why they can spin their heads all the way around.

 

[Chew Toy McCoy]

Video showing spiders hunting in packs is pure nightmare fuel

A startling new video of spiders hunting in packs is the perfect example of nightmare fuel you never needed.

bgr.com

“The spiders weave massive nonstick webs and then wait for bugs to run into them. When they feel the vibrations in the web, the spiders hunt in packs moving towards the bug in synchronized motion. They stop whenever their own movements threaten to drown that of their prey, resulting in weird stop-animation-like movements.”

 

[lizkat]

The latest on jumping spiders: they may exhibit eye movement similar to that of humans during REM sleep.

Jumping spiders may experience something like REM sleep

If it's an analog of mammalian REM sleep, then it evolved very early.

arstechnica.com