Title photo: Female. Photo by Gwendolyn Gunn on 8/24/20 near Red Lodge, MT.

There are approximately 3,500 species of orb weavers worldwide. With 180 occurring north of Mexico and more than 50 of those species in this genus, we weren’t able to narrow down these beauties further. For most orb weavers, the ability to classify a specimen to species level often requires a microscopic inspection of the genitalia.

Male. Photo by Madeline May on 8/22/20 in Lolo, MT.

These spiders are best known for the beautiful, wheel-shaped webs they construct and are often found around the outside of your house and in gardens, fields and forests. By this time of year, it’s hard not to notice the females, which have grown pretty large. Exhibiting significant sexual size dimorphism, adult male orb weavers are much smaller and are not seen as often (generally do not spin webs). Males are also reportedly “leggier.”

Male. Photo by Cassy Geiser on 8/27/20 in Hamilton, MT.

Before the first hard frost hits and kills off this year’s crop of weavers, the females will lay one or more egg sacs, each containing up to several hundred eggs, that will survive the winter. Most nocturnal orb weavers are usually brown or gray in color. Diurnal species exhibit bright colors of yellow or orange along with black markings