title: Heterogeneity in individual quality and reproductive trade-offs within species.
abstract: Interspecifically, a reasonable body of evidence supports a trade-off between offspring size and number. However, at the intraspecific level, a whole manner of phenotypic correlations between offspring size and number are observed. These correlations may be predicted when heterogeneity in resource availability, or quality, is considered. Making the assumption that maternal size is a proxy for resource availability, we meta-analytically quantified four phenotypic reproductive correlations within numerous species: (1) maternal size and offspring size, (2) maternal size and offspring number, (3) offspring number and offspring size, and (4) offspring number and offspring size after controlling for maternal size. Within species, maternal size showed a positive correlation with both offspring size and number. Despite this consistency, no correlation between offspring size and number was found. After controlling for maternal size, however, offspring size and number showed a significant negative correlation. A phylogenetic component of our analysis accounted for little heterogeneity in the data, suggesting that our findings show remarkable consistency across taxa. Overall, our results support an observable phenotypic trade-off between offspring size and number. However, this analysis also highlights the importance of considering quality when examining trade-offs, a task that is not always straightforward as quality is context dependant.
authors.affiliation: Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9054, New Zealand.
authors.forename: Jiahui N
authors.initials: JN
authors.lastname: Lim
authors.forename: Alistair M
authors.initials: AM
authors.lastname: Senior
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D049628:Body Size; D052284:Clutch Size; D005260:Female; D008954:Models, Biological; D010641:Phenotype; D012098:Reproduction
keywords: Clutch size; life-history theory; litter size; optimum offspring size; resource acquisition; resource allocation