As web is to spider.
An antlion. First half of antlion is 'ant'.
cove
They are called infants
The common name for spider silk is "cobweb."
As web is to spider.
The Brown Widow spider makes a brown, spilt nest.
Nest
harvestman spider
A nest, or a bird house.
Aerie
Yes!
It could be a nest or hive.
Fiddler Crab
The spider is commonly called the "Mediterranean widow spider." "Marmaga" is just another common name for it which doesn't appear to have an English translation.
you could throw it to a tree
A sajou is another name for a spider monkey or capuchin.