How Does Metabolic Rate Scale With Egg Size? An Experimental Test With Sea Urchin Embryos

Amy L. Moran, Jonathan D. Allen
2007 The Biological Bulletin  
The consequences of changes in egg size for the development of marine invertebrates have been the subject of much theoretical and experimental work. Models that explore larval developmental modes in the context of maternal investment per offspring are often couched in an energetic framework, but the relationships between egg size and the energetics of larval development are poorly understood. We used blastomere separations to examine how experimental reductions in egg size affected (1) larval
more » ... fected (1) larval metabolic rate and (2) larval resistance to starvation. We found that separating blastomeres at the 2-and 4-cell stage resulted in average reductions of 50% and 75%, respectively, in larval metabolic rate. This suggests that, in an experimental context, mass-specific metabolic rate does not change with egg size. We also found that a 50% reduction in egg volume did not reduce the resistance of larvae to starvation when particulate food was withheld. This suggests that the material supplied to larvae in the egg is used primarily for construction of the larval body, rather than as a buffer against starvation or as a means of reducing reliance on exogenous fuel to sustain maintenance metabolism. Literature Cited Allen, J. D. 2005. Life-history evolution and the costs of small egg size in echinoderms. Ph.D dissertation, University of North Carolina, Chapel Hill. 150 pp. Allen, J. D., C. Zakas, and R. D. Podolsky. 2006. Effects of egg size reduction and larval feeding on juvenile quality for a species with facultative-feeding development. . 1996. Twins raised from separated blastomeres develop into sexually mature Strongylocentrotus purpuratus. Dev. Biol. 178: 514 -519. Cushing, D. H. 1990. Plankton production and year-class strength in fish populations: an update of the match/mismatch hypothesis. Adv. Mar. Biol. 26: 249 -293. Dan-Sohkawa, M., and N. Satoh. 1978. Studies on dwarf larvae devel-
doi:10.2307/25066591 pmid:17438206 fatcat:bxfvqhapzveoxhfnk5bcifb7cm