Rosie

Rosie is a black widow spider who has a mother-like nature. She is mostly like a mother to the rhinoceros beetle, Dim, with whom she shares an act, and also the younger ants of the colony. She has apparently had twelve husbands who all died, making her (as she says) a "black widow widow." She sees her circus friends as her only true family.

Rosie works at P.T. Flea's circus as a rhinoceros tamer with her partner being the rhinoceros beetle Dim. But she and her circus friends are fired after they accidently burn P.T.

At a bar, they got into a fight with some flies and Flik thought they were warriors and they thought that Flik was a manger searching for entertainment. She, along with her friends, flew to Ant Island

She is the one that tells Flik that they are circus artists and not warriors; after that, they attempt to leave the island but are stopped by the attack of the bird. Rosie participates in the rescue of Dot and Francis by making a web to transport Flik, Dot, Francis, Tuck and Roll to safety. It is interesting to note that Rosie is very strong, as she carried the spider web with Flik, Dot, Francis, Tuck and Roll inside and when it was cut accidently, Rosie held them long enough to land on a tree.

After the rescue, the Circus bugs agrees to stay and support Flik's idea of making an artifical bird to scare the Grasshoppers away. Rosie participates in the making of the bird and then, at a party, she talks with an ant about her 12 deceased husbands. At the climax of the film, she participates in the final battle against the Grasshoppers and then she and her friends leave the Island with the promise of returning next spring.