Micrathena gracilis
Copyright, Charles S. Lewallen
The Spined Micrathena is
one of our most common spiders. If you've ever walked
through a spider web in the woods, it was very likely a
micrathena's web. Usually, it is only the
female spider that is seen. She is about 1/2 inch long, with
a chunky abdomen that has ten spines on it. The abdomen
varies in color; usually it is whitish, yellow, or
brownish-black. The cephalothorax (front section) is much
smaller than the abdomen, and it is amber-colored. This
spider's legs are glossy black. Copyright, Richard
Bradley, Spiders
In Ohio Copyright, Jeffrey K.
Barnes The male Spined
Micrathena is about half the size of the female. It has only
a couple of spines and a much flatter abdomen. Only females
build webs. To trap prey, the Spined
Micrathena builds her web between shrubs or small trees,
three to seven feet off the ground. Insects that try to fly
in between the trees don't see the web and get stuck. First,
the micrathena weaves three main lines of web; then she
builds her orb (circular part of the web). The orb is six to
eight inches across. As soon as the sun goes down, she eats
her web. When the sun comes up, she builds it again. The
silk for the web comes from the tip of her abdomen. She
weaves the silk with her hind legs. Most of the prey that get
caught in the web are small flies, such as mosquitoes and
gnats. Small wasps, flying ants, and beetles also get
caught. The micrathena hangs out in the center of her web,
with her head pointing down. As soon as she feels the
vibrations of prey trapped in her web, she runs to bite it.
These spiders are slow and clumsy. Many insects escape
before she can catch them. When she catches one, she bites
it first, then wraps it in silk. Male micrathenas do not
build webs, but they do weave a "mating thread." The male
finds a female's web, and weaves his mating thread onto her
web. When he's ready, he quickly runs out and mates with
her. Males often do not survive the encounter. The female makes a tan
sphere with silk and lay her eggs inside it. She lays the
sphere on plants near her web. Eggs are laid in
September. Spined Micrathenas have
only one generation each year. Eggs overwinter in their sac
and hatch the next year. Young spiders become fully grown by
July and are ready to mate. Copyright, Tam
Stuart Mark Moran Mark Moran
