Water spider build diving bell webs which are used for digesting prey, although only the female's larger bell is used for mating and raising offspring. Females spend most of their time within their bells, darting out to catch prey animals that touch the bell or the silk threads that anchor it and occasionally surfacing to replenish the air within the web. The bells built by males are typically smaller than females and are replenished less often. Mating takes place in the female's bell.