Gregorsa pointing out Formicosa B-1
Formicosa B-1 is a subterranean region located beneath Formicosa Apex in the Tricularia System. It is known for being the birthplace of Rose. Formicosa B-1 is not just home to arachnids.
It is home to the world's largest Arachnid Nest, as well as multiple ant factories where they can work (though what these factories make, exactly, is known only to the ants). It also has a Roach Nest and a Beetle Nest, as well as other insect Nests that are minor enough to be considered sisters to the other two. Some Nests in Formicosa City, however, use B-1 as a nursery. And, despite the fact that no ants live here, it is crawling with them.