Heterozygosity and energetics of growth in suspension-feeding bivalves: A re-examination

Abstract

A growing literature deals with possible relationships between heterozygosity and physiological performance, including growth and metabolism. An important part of these studies deals with marine suspension-feeding bivalves. It is the predominant view that fitness is correlated with multilocus heterozygosity, which may thus be important in an ecological and evolutionary context. It has been suggested that heterozygosity-dependent increases in growth are associated with low levels of maintenance requirements, savings in energy being utilized in growth and survival. Re-examination of the data upon which this hypothesis is based showed the interpretations to be untenable. It is argued that a main reason for the ambiguity of existing data on relationships between heterozygosity and growth in suspension-feeding bivalves is insufficient regard to the plasticity in bivalve behaviour, reflecting environmental conditions. It is concluding that successful assessment of the role of heterozygosity in bivalve growth depends upon knowledge about the adaptability of feeding, growth and metabolism in the population studied.