A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Is extrapair mating random? On the probability distribution of extrapair young in avian broods
Tekijät: Brommer JE, Korsten P, Bouwman KA, Berg ML, Komdeur J
Kustantaja: OXFORD UNIV PRESS INC
Julkaisuvuosi: 2007
Lehti:: Behavioral Ecology
Tietokannassa oleva lehden nimi: BEHAVIORAL ECOLOGY
Lehden akronyymi: BEHAV ECOL
Vuosikerta: 18
Numero: 5
Aloitussivu: 895
Lopetussivu: 904
Sivujen määrä: 10
ISSN: 1045-2249
DOI: https://doi.org/10.1093/beheco/arm049
Tiivistelmä
A dichotomy in female extrapair copulation (EPC) behavior, with some females seeking EPC and others not, is inferred if the observed distribution of extrapair young (EPY) over broods differs from a random process on the level of individual offspring (binomial, hypergeometrical, or Poisson). A review of the literature Shows such null models are virtual]), always rejected, with often large effect sizes. We formulate an alternative mill model, which assumes that 1) the number of EPC has a random (Poisson) distribution across females (broods) and that 2) the probability for an offspring to be of extrapair origin is zero without any EPC and increases with the number of EPC. Our brood-level model can accommodate the bimodality of both zero and medium rates of EPY typically found in empirical data, and fitting our model to EPY production of 7 passerine bird species shows evidence of a nonrandom distribution of EPY in only 2 species. We therefore argue that 1) dichotomy in extrapair mate choice cannot be inferred only from a significant deviation in the observed distribution of EPY from a random process on the level of offspring and that 2) additional empirical work on testing the contrasting critical predictions from the classic and our alternative null models is required.
A dichotomy in female extrapair copulation (EPC) behavior, with some females seeking EPC and others not, is inferred if the observed distribution of extrapair young (EPY) over broods differs from a random process on the level of individual offspring (binomial, hypergeometrical, or Poisson). A review of the literature Shows such null models are virtual]), always rejected, with often large effect sizes. We formulate an alternative mill model, which assumes that 1) the number of EPC has a random (Poisson) distribution across females (broods) and that 2) the probability for an offspring to be of extrapair origin is zero without any EPC and increases with the number of EPC. Our brood-level model can accommodate the bimodality of both zero and medium rates of EPY typically found in empirical data, and fitting our model to EPY production of 7 passerine bird species shows evidence of a nonrandom distribution of EPY in only 2 species. We therefore argue that 1) dichotomy in extrapair mate choice cannot be inferred only from a significant deviation in the observed distribution of EPY from a random process on the level of offspring and that 2) additional empirical work on testing the contrasting critical predictions from the classic and our alternative null models is required.
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