Effects of Annual Rainfall on Reproduction of Pleurodema tucumanum (Anura: Leptodactylidae) on the Western Border of the Great American Chaco

Abstract

The objective of this study was to describe and compare the reproductive cycle of Pleurodema tucumanum in dry and rainy years in a portion of the Chaco Serrano in western Argentina. We captured 141 males and 93 females during their months of activity between 2011 and 2015. Adults were sexed and their body size and weight were determined. We weighed fat bodies and calculated testis volume in males and fecundity in females. Fecundity was based on the number of mature oocytes present in the ovary, the ovarian complement. Like many species of the family Leptodactylidae, this species presents sexual dimorphism, with females being larger than males. The reproductive variables showed no significant differences between dry and rainy years. Linear regression analyses between abiotic factors (maximum temperature, minimum temperature, and accumulated rainfall) and reproductive variables showed significant positive relationships. Both in dry and rainy years, we recorded the presence of atretic follicles and developing and maturing oviducts. In rainy years, mature oocytes were observed from November through April, and from October to March in dry years (local summer). Only in dry years were significant variations observed in fat body weight during the reproductive season. Annual cycles of rainy periods do not affect the reproductive activity of this species, which appears to be a strategy for its permanence in this Chacoan region.