Reproductive strategies in Akodon azarae (Rodentia, Muridae)
The balance between litter size and the quality of offspring is a central feature to many optimal litter-size theories. We analyzed the reproductive strategies of Akodon azarae (Fischer, 1829) females, according to maternal life histories and the time of birth. Litter size decreased significantly fr...
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| Autores principales: | , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00084301_v82_n10_p1572_Suarez |
| Aporte de: |
| Sumario: | The balance between litter size and the quality of offspring is a central feature to many optimal litter-size theories. We analyzed the reproductive strategies of Akodon azarae (Fischer, 1829) females, according to maternal life histories and the time of birth. Litter size decreased significantly from spring to autumn. A significant birth-season effect on mass at birth was observed. A compensatory effect of growth rate was evident during lactation. During spring and early summer, over-wintered females produced an average of 5 young, with maximum survival at weaning (100%). Females born during the current reproductive season showed a smaller litter size, probably because they favor residual reproductive value with respect to current reproduction since they have a higher life expectancy and future chances of mating than over-wintered females. Mortality reached 50% at weaning for summer litters from young mothers, whereas it declined to 22.2% in autumn. Differences in both parental investment and offspring survival suggest that litter size in A. azarae varies along the reproductive period and is dependent both on females' life history and on environmental conditions. © 2004 NRC Canada. |
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