On Reproductive Strategies in Marine Benthic Invertebrates

Abstract

Mathematical models are described relating reproductive energetic efficiency to egg size in marine benthic invertebrates with planktonic and nonplanktonic prefeeding larval development. The models are based on simplified assumptions concerning planktonic and benthic predation and the relations between egg size and method of larval nutrition and between egg size and duration of larval life. The model's predictions include: (a) only the extremes of the possible range of egg size and method of nutrition (i.e., planktotrophy, lecithotrophy) are evolutionarily stable; (b) over a certain range of environmental parameters, the two developmental modes are both evolutionarily stable; (c) planktotrophy is more efficient than lecithotrophy when planktonic food is abundant and planktonic predation low, and lecithotrophy more efficient when either or both of these conditions is reversed; and (d) benthic prefeeding development results in greater efficiency when lecithotrophic development time is long and/or planktonic predation more intense than benthic predation, and planktonic prefeeding development is more efficient when these conditions are reversed. Known geographic trends in developmental patterns are discussed in light of these results, and possible explanations for these trends are offered. Ways of testing the predictions and explanations of geographical trends are suggested.