Study of lipid reserves in Liolaemus koslowskyi (Squamata: Liolaemidae): reproductive and ecological implications
In reptiles, many lipid reserve structures were recognized, and different patterns of storage and utilization of lipids have been identified. In this study, a population of Liolaemus koslowskyi was studied to analyze the diversity and functioning of the lipid reserve structures. The specific objectives were to identify the main lipid reserve structures, and to describe their seasonal patterns; to study sexual and seasonal variations of the reserve structures; and to analyze the relation between seasonal patterns of such reserves with the sexual cycle and other biological aspects. Individuals of both sexes collected at five different times of the year were analyzed. The abdominal fat bodies, livers, tails, fat deposits of the lateral folds of the neck, the fat bodies of the axillary region and gonads were weighted. The fat content of livers, tails and neck fat reserves were determined through the extraction in a Soxhlet device. The volume of the ovaries, oviductal oocytes and testicles, and the average surface and thickness of the epididymides were estimated. The abdominal fat bodies and the tail-extracted fats were the main lipid reserves. In general, females showed higher lipid contents, and significant seasonal variations in weight and lipid content in both sex were found, while seasonal variations in the liver fresh weight and liver fat content were found only in males. The axillar and neck fats deposits probably function as auxiliary reserves, and the caudal autotomy did not significantly affect tail fat content. The sexual cycles were synchronic in both sexes.