Authors: Richard M Allen and Dustin J Marshall
Published in: PloS ONE, volume 9, issue 7 (July 2014)
The optimal balance of reproductive effort between offspring size and number depends on the fitness of offspring size in a particular environment.
The variable environments offspring experience, both among and within life-history stages, are likely to alter the offspring size/fitness relationship and favor different offspring sizes. Hence, the many environments experienced throughout complex life-histories present mothers with a significant challenge to optimally allocate their reproductive effort.
In a marine annelid, we tested the relationship between egg size and performance across multiple life-history stages, including: fertilization, larval development, and post-metamorphosis survival and size in the field.
We found evidence of conflicting effects of egg size on performance: larger eggs had higher fertilization under sperm-limited conditions, were slightly faster to develop pre-feeding, and were larger post-metamorphosis; however, smaller eggs had higher fertilization when sperm was abundant, and faster planktonic development; and egg size did not affect post-metamorphic survival.
The results indicate that egg size effects are conflicting in H. diramphus depending on the environments within and among life-history stages. We suggest that offspring size in this species may be a compromise between the overall costs and benefits of egg sizes in each stage and that performance in any one stage is not maximized.
Allen RM, Marshall DJ (2014) Egg size effects across multiple life-history stages in the marine annelid Hydroides diramphus. PLoS ONE 9(7): e102253 PDF 250 KB diramphus doi:10.1371/journal.pone.0102253