Lim Jiahui N, Senior Alistair M, Nakagawa Shinichi
Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9054, New Zealand.
Evolution. 2014 Aug;68(8):2306-18. doi: 10.1111/evo.12446. Epub 2014 Jun 3.
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.
在种间水平上，有相当数量的证据支持后代大小和数量之间的权衡。然而，在种内水平上，观察到了后代大小和数量之间各种各样的表型相关性。当考虑资源可用性或质量的异质性时，这些相关性是可以预测的。假设母体大小是资源可用性的一个指标，我们通过荟萃分析量化了众多物种内的四种表型繁殖相关性：（1）母体大小和后代大小，（2）母体大小和后代数量，（3）后代数量和后代大小，以及（4）在控制母体大小后后代数量和后代大小。在物种内部，母体大小与后代大小和数量均呈正相关。尽管存在这种一致性，但未发现后代大小和数量之间存在相关性。然而，在控制母体大小后，后代大小和数量呈现出显著的负相关。我们分析中的系统发育成分在数据中解释的异质性很小，这表明我们的研究结果在不同分类群中具有显著的一致性。总体而言，我们的结果支持在后代大小和数量之间存在可观察到的表型权衡。然而，该分析还强调了在研究权衡时考虑质量的重要性，而这一任务并不总是那么直接，因为质量取决于具体情境。
