Anyone who has seen Charlotte’s Web knows a little about how spiderlings hatch. Charlotte, the spider, hangs her egg sac on a web inside the barn where she and the pig, Wilbur, live. She stands watch over the egg sac, giving her last pieces of wisdom to her friend. After she dies, Wilbur is grief-stricken until one morning, the egg sac hatches, releasing many spiderlings at once. Three remain to keep him company. This scenario is actually pretty accurate for a Nursery Web Spider.
The mother of this particular species actually creates a web where she will hang her egg sac and guard it while the spiderlings develop. Not all females hang around once they lay the eggs into the sac and hang it out of sight. The egg sac is made of spider silk. The eggs are laid onto it and it is then gathered up into a ball shape. Females carry the egg sac under their bodies. They look like tiny white golf balls. They carry it to a shrub or other vegetation and create a nursery for it by spinning a web that it can hang from. Then she waits, watching over her egg sac.
Once the tiny spiders inside grow enough to form appendages, the egg sac splits open, and a hundred or more miniature spiders exit the sac in all directions. Some head straight away, others linger for a while. Wherever they finally reside, they’ve all been given a better start in life because of a mother that guarded them, moving them from danger if she had to, increasing the likelihood that her line will carry on.