There are different species of spiders.
Latrodectus . The genus contains 31 recognized species distributed worldwide , including the North American black widows ( L. mactans , L. hesperus , and L. variolus ) , the button spiders of Africa , and the Australian redback spider . Spider . They are the largest order of arachnids and rank seventh in total species diversity among all other orders of organisms . A herbivorous species , Bagheera kiplingi , was described in 2008 , but all other known species are predators , mostly preying on insects and on other spiders , although a few large species also take birds and lizards . Females of many species care for their young , for example by carrying them around or by sharing food with them . A minority of species are social , building communal webs that may house anywhere from a few to 50,000 individuals .