The Life Cycle of a Common House Spider
Female common house spiders (Parasteatoda tepidariorum) deposit as many as 250 eggs into a sac of silk. These sacs are often brown in color and are flask-like in shape. Females produce up to 17 of these sacs during a lifetime, resulting in more than 4,000 eggs.
Within a week, spiderlings hatch and begin to undergo a series of instars. The first instar takes place inside the egg sac. Males undergo six instars, while females undergo seven. After hatching, air currents disperse surviving spiderlings on threads of silk. This process, known as ballooning, allows spiders to populate habitats far from their origin.
Adult specimens may survive for more than a year. Their exteriors and sternums are yellow or brown in color. Their abdomens are gray and marked with white, while their legs are brown and darkly banded. Males are smaller than females, measuring only 4 mm in length as opposed to the female’s 8 mm.