"Daddy long legs" eat them, but I'm not sure which daddy long legs.
There's a spider in the Pholcidae family, called a "Daddy longleg", (which is harmless to humans, despite the silly myths circulating).
And there is a creature, the "Harvestman", called a daddylongleg (which is an not really a spider).
I think it is the Pholcidae (the daddy longleg spider), that eats them.
It can just be a red back spider...
a wolf spider. they hurt but are not deadly to humans
A spider.
The spider that is black with a white crescent on its back is the Brown House Spider. This spider is often confused with the red-back spider.
a red back.
red back spider
A black widow spider is black with a red mark on it's abdomen; this might or might not be what you meant. The black widow sometimes has a red mark on her back, as well. The red backed spider of Australia, a relative of the black widow, has an orange red mark on the back.
a spider.
red back
Arachnic
Have seen a very small spider with 4 white dots and 1 red dot. Not a red back. Ta ~Snaff
A green spider with a red spot is dangerous if it is a red back. Normally, green spiders are not dangerous.