The Reproductive Cycle of Sceloporus undulatus From Alabama Corresponding Plasma Steroid Levels and Comments on Reproductive Variation.

Eastern fence lizards from Alabama were captured and reproductive parameters were measured. In males, the height of the breeding season (spermiogenesis and spermiation) occurred from March to May. Testis mass declined during this time. Spermatozoa were present in the epididymides until July. In June and July, testis mass was minimal. A new spermatogenic cycle had begun by August. Testicular recrudescence occurred in fall with concomitant increase in testis mass. Males had spermatids with a few transforming spermatozoa in their testes as they entered brumation. The longer warm season in Alabama permitted the males to begin spermiogenesis and spermiation earlier and to complete fall recrudescence later than Missouri S. undulatus. Plasma testosterone levels in the males peaked soon after emergence from brumation, declined during spring breeding, and rose again in the fall. These changes were concomitant with changes in testis mass and spermatogenesis.Females emerged from brumation slightly later than the males and immediately began vitellogenesis. Older female fence lizards had at least 3 clutches per season. Eggs were oviposited in May, June, and July. Most yearlings had either 1 or 2 clutches per season. Alabama females were similar to other southern populations examined (South Carolina; Texas ; Lordsburg, New Mexico) in that the Alabama population was highly reproductive.Seasonal steroid changes in this multi-clutched, oviparous squamate were examined. Plasma estrogen levels were slightly elevated during the luteal phases of the first two clutches and peaked during the last clutch. Plasma progesterone and testosterone were low and reached high levels during the last clutch. Preovulatory surges of plasma estrogen, progesterone, and testosterone were observed in yearling females captured in July. Whether similar surges occur with each clutch is unknown. Minimum levels of steroids were observed in overwintering animals.Fat body and liver masses in male and female fence lizards increased in fall and decreased in spring soon after emergence from brumation. Changes in females were more marked than in males. In spring, fat stores were likely used for mating behavior, maintenance, territorial displays (males), and vitellogenesis (females). In addition, steroid levels in both male and female lizards increased as fat body weight decreased in spring, suggesting fat depletion during steroidogenesis. 

Level thesis:degree_level

Thesis

Year

1982

Author dc:creator

• McKinney, Rose Brackin

• Brumation
• Spermatids
• Plasma testosterone
• Spermatogenic cycle
• Eastern fence lizards

Repository record dc:identifier

https://digitalcommons.library.uab.edu/etd-collection/7138

OAI identifier oai:identifier

oai:digitalcommons.library.uab.edu:etd-collection-8130