Answer:
It is worldwide, but once only a spider could weave one
Round as an apple, deep as a cup, and all the kings' horses can't fill it up. What is it?
What is the thing which, once poured out, cannot be gathered again?
Only one color, but not one size. Stuck at the bottom, yet easily flies. Present in sun, but not in rain. Doing no harm, and feeling no pain.
A mighty weapon in the war against winged household pests.
Before I grow I'm small. When I'm old I grow tall. When I die I give a mighty fall.