This week, my technician Greg VanNostrand found a black widow in our storage Quonset at the ISU Johnson Research Farm. The farm is just south of Ames in Story County. She is an adult female and had a pile of dead body fragments below her web. Needless to say, she was healthy and happy in the Quonset. But Greg likes spiders and decided to bring her back to my lab (thanks?). He has successfully kept black widows (and other spiders) by feeding them flies from colonies in the Insectary.
Why do we care about black widow spiders? The females are considered highly venomous, but human deaths are rare compared to the number of people envenomated. People bitten by a female black widow may have swelling, redness, muscle pain, nausea, headache, and cramping. The venom contains several toxins and in general sounds like a painful experience. The good news is they are predators, and eat insects and pretty much anything that gets caught in their web. There are a few species of black widow in the U.S. and they have a wide distribution in the southern states. It is possible for black widows to live in Iowa, but finding them here is more likely because they were accidentally introduced instead of established.
It was hard to take a good picture of the male and female spiders through the plastic rearing chambers in my lab. I didn't feel brave enough to take the lids off and get a close-up.