Reposting this from 2 years ago.
This is Charlotte – Charlie for short. She is a female daddy longlegs spider, aka cellar spider, family Pholcidae. I’ve been watching her since she was a tiny spiderling who happened to show up in the corner outside a window. My, my, they grow up so fast!
It is a good place for her. It is high enough that the dogs aren’t interested and sheltered enough that birds won’t bother her. There is a light nearby to attract flying insects at night and flies like to hang out there, in the shade and out of the wind, during the day. It is my hope that Charlotte will grow strong and have lots of spiderlings of her own.
It isn’t all just empty nest syndrome and redirected parental urges. Daddy longlegs are my favorite spiders, even more so than the magnificent yellow and black orb weavers. As far as humans go, they are as harmless as a spider can get. They have an interesting web. It uses a velcro type of adhesion rather than a sticky surface to ensnare insects. They are also social spiders, often with several sharing a large web. One species of longlegs reacts to a potential threat by vibrating itself so fast it becomes almost invisible.
I have never seen widows anywhere near a daddy longlegs nest. I understand that widows are one of their favorite foods and that the velcro-like webbing makes their own webs difficult to traverse for other spiders. They hunt the other spiders down, then shoot lines of web over the prey from a distance. When the prey is immobilized they move in for a large dinner.
If I see a widow near a high traffic area I will kill it. If it is off in the bush where it can harm neither man nor dog, I let it be. If another species of spider makes life difficult for widows, more power to it. You are welcome in my home. I think of it as biological pest control.
Because people are very quick to kill any black spider they see, the brown widow is becoming more common in the west. The brown widow injects far less venom when it bites, so if it eventually takes over the black widow’s niche I’ll be happy. Black widow bites are very serious for the young, the very old and for house pets.
I expect that longlegs will find brown widows just as tasty.