Sexual size dimorphism and testis size allometry in tuco-tucos (Rodentia: Ctenomyidae)

We studied sexual size dimorphism (SSD) and testes size allometry in 97 natural populations, including 39 nominal species and 19 unnamed or undescribed forms, of tuco-tucos ( Ctenomys ) from Argentina, Bolivia, Chile, Paraguay, and Uruguay in order to gain insight on the existence of sperm competiti...

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Detalles Bibliográficos
Autores: Bidau, Claudio Juan, Medina, Alonso Ismael
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2013
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/17651
Acceso en línea:http://hdl.handle.net/11336/17651
Access Level:acceso abierto
Palabra clave:Renschs Rule
Sexual Size Dimorphism
Sexual Selection
Testis/Body-Size
Allometry
Tuco Tucos
https://purl.org/becyt/ford/1.6
https://purl.org/becyt/ford/1
Descripción
Sumario:We studied sexual size dimorphism (SSD) and testes size allometry in 97 natural populations, including 39 nominal species and 19 unnamed or undescribed forms, of tuco-tucos ( Ctenomys ) from Argentina, Bolivia, Chile, Paraguay, and Uruguay in order to gain insight on the existence of sperm competition in these solitary, territorial, and possibly polygynic subterranean rodents. Our results indicated that sex-biased SSD occurs within the genus and also within lower taxa. SSD conforms to Rensch ’ s rule. Testes size showed a strong negative allo metry when compared with male body mass both across and within species, clearly suggesting the operation of sperm competition in this genus. Thus, within a Ctenomys population, small males would invest more than larger males in testes growth and thus in ejaculate quality, which would counterbalance their presumably lower chances of accessing females due to their smaller body size.