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Within-Clutch Patterns of Egg Viability and Paternity in the House Sparrow
Pedro J. Cordero, Jon H. Wetton and David T. Parkin
Journal of Avian Biology
Vol. 30, No. 1 (Mar., 1999), pp. 103-107
Stable URL: http://www.jstor.org/stable/3677249
Page Count: 5
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One of the potential benefits of extra-pair copulation is an enhanced likelihood of successful fertilization if the pair male is unable to produce sufficient viable sperm to ensure the fertility of an entire clutch. Low male fertility can be a transient phenomenon associated with higher rates of sperm usage than production, leading to a progressive depletion of sperm reserves. Evidence of a correlation between hatching success and the occurrence of extra-pair fertilizations has been reported in House Sparrows. In this study we have used single-locus minisatellite and microsatellite profiling to investigate the distribution of extra-pair fertilizations within House Sparrow broods to determine whether there are changes in the level of hatching failure or extra-pair paternity during the course of producing a clutch. Embryonic material was collected at mid-incubation to minimize loss of data through pre-sampling mortality and to ensure that laying order was known. A significant clustering of both infertile eggs and extra-pair young was noted in the earliest eggs in a clutch. Possible causes of this phenomenon are discussed.
Journal of Avian Biology © 1999 Nordic Society Oikos