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LARGE VARIANCE IN REPRODUCTIVE SUCCESS AND THE Ne/N RATIO
Author(s) -
Hedrick Philip
Publication year - 2005
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2005.tb01809.x
Subject(s) - biology , reproductive success , variance (accounting) , statistics , evolutionary biology , demography , mathematics , population , accounting , sociology , business
The ratio of the effective population size to adult (or census) population size (N e /N) is an indicator of the extent of genetic variation expected in a population. It has been suggested that this ratio may be quite low for highly fecund species in which there is a sweepstakes‐like chance of reproductive success, known as the Hedgecock effect. Here I show theoretically how the ratio may be quite small when there are only a few successful breeders (Nb) and that in this case, the N e /N ratio is approximately N b /N. In other words, high variance in reproductive success within a generation can result in a very low effective population size in an organism with large numbers of adults and consequently a very low N e /N ratio. This finding appears robust when there is a large proportion of families with exactly two progeny or when there is random variation in progeny numbers among these families.