Sperm parameters associated to reproductive ecology in two snakes species

• Autores: Tourmente, Maximiliano; Giojalas, Laura Cecilia; Chiaraviglio, Margarita
• Año de publicación: 2011
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Snakes; Sperm Competition; Sperm Dynamic Parameters; Temperature Effects
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The effect of temperature on sperm dynamic parameters in ectotherms in general, and reptiles in particular, remains poorly understood due to the lack of consistent evidence. As a group, snakes show considerable variability regarding mating systems, male reproductive behavior, thermoregulatory behavior, and preferred temperatures. Additionally, snakes present significant variability in sperm competition levels, which is determined by the species mating system. Because sperm longevity, motility, and velocity are positively related to reproductive success in both competitive and noncompetitive conditions, the sperm physiology of ectothermic organisms may functional optimally at ecologically relevant temperatures. The objective of this work was to analyze the effect of an ecologically plausible range of temperatures on sperm dynamic parameters of two species of snakes with contrasting mating systems and sperm competition levels: Boa constrictor occidentalis and Waglerophis merremii. To accomplish this, an in vitro incubation approach was used: sperm dynamic parameters (i.e., motility and velocity) were measured on sperm solution aliquots incubated at 25uC, 30uC, and 37uC for up to 10 h by means of a phase contrast video microscopy system. Results suggested that although an increase in temperature has a general negative impact on sperm motility and velocity, the two species studied present different degrees of sensitivity to high incubation temperatures. Moreover, these differences can be explained by the dissimilar thermal conditions that the sperm of the two species would experience during their reproductive seasons, which are a consequence of the differences in their reproductive behavior. In conclusion, sperm motility and swimming velocity respond mainly to environmental conditions imposed by mating systems rather than to selection by sperm competition.
Fil: Tourmente, Maximiliano. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Diversidad Biológica y Ecologica; Argentina
Fil: Giojalas, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Biología Celular y Molecular; Argentina
Fil: Chiaraviglio, Margarita. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica. Cátedra de Biología del Comportam. y Div. Animal Ii; Argentina