Diet and reproductive biology of the viviparous lizard Sceloporus torquatus torquatus (Squamata : Phrynosomatidae)

The reproductive cycle and diet of a population of the viviparous lizard Sc eloporus torquatus torquatus from the Pedregal de San Angel, Distrito Feder al, Mexico, were studied. Ovarian activity began in June,and by October, on e to five preovulatory follicles per ovary were present Ovulation took plac e in November and December, and parturition occurred in late April or early May. Relative titter and egg masses were higher at the end of development than at the beginning. Testes increased in size from June through September , when they reached their maximum volume and weight Testicular regression b egan at this point and was particularly accentuated in October and November . The diet of both sexes was composed primarily of insects; however, plant material (small flowers and fruits), spiders, isopods, and occasionally ear thworms were also consumed. Both sexes consumed plant material throughout t he year. In the dry season, males ingested twice as much food as females.