Maternal energy investment in eggs and jelly coats surrounding eggs of theechinoid Arbacia punctulata

In free-spawning marine invertebrates, the amount of maternal energy that i s invested in each egg has profound implications for all life-history stage s of the offspring. The eggs of echinoids are freely spawned into the water and are surrounded by several structurally complex extracellular layers. T hese extracellular layers, or jelly coats, do nor contribute energy to embr yonic development but must impose an energy cost on the production of each egg. The investment of maternal energy reserves in the jelly coats of echin oid eggs malt have important implications for the number of eggs that can b e produced (i.e., fecundity) and the amount of energy that can be invested in each egg. We estimated the degree to which maternal energy is invested i n the jelly coats surrounding eggs of the echinoid Arbacia punctulata. Esti mates were derived from measurements of the amount of energy contained in t he combined eggs and jelly coats, and in the eggs alone. The amount of ener gy contained in A. punctulata eggs ranged from 2.70 to 5.53 X 10(-4) J egg( -1). The amount of energy contained in the jelly coats ranged from 0.13 to 0.48 X 10(-4) J jelly coat(-1). The mean concentration of energy in the egg s was 2.15 mm(-3) and 0.29 J mm(-3) in the jelly coats. These results indic ate that between 3% and 11% (mean = 7%) of the total energy invested in eac h A. punctulata egg is partitioned to the jelly coat alone. A significant p ositive relationship was found between the volumes of the jelly coats and t he amount of energy they contained. Based on this relationship and an analy sis of differences in the size of jelly coats between echinoid species, we suggest that the degree to which energy is invested in jelly coats may vary among echinoid species and is therefore likely to be an important life-his tory characteristic of these organisms.