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OPTIMUM BROOD SIZE: TESTS OF ALTERNATIVE HYPOTHESES
Author(s) -
Morris Douglas W.
Publication year - 1992
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.1558-5646.1992.tb01173.x
Subject(s) - biology , brood , litter , alternative hypothesis , abundance (ecology) , avian clutch size , population , population size , ecology , zoology , statistics , demography , reproduction , null hypothesis , mathematics , sociology
The most productive litter size (five) was not as common as expected in a free‐living population of white‐footed mice. I evaluated four competing hypotheses that can explain this pattern. Reproductive costs and annual variation in recruitment appear to be insufficient explanations for the empirical distribution of litter size. Optimal investment of reproductive resources that vary among parents is supported by some tests, but not by all. The abundance of litters less than the apparent optimum is at least partially explained by asymmetric survival in large litters (the cliff‐edge hypothesis). Hypotheses that explain the empirical distribution of brood size are not mutually exclusive. Several mechanisms can act alone, or interact, to create an average brood size less than that which appears to produce the greatest number of descendants.