Patterns of growth and chemical composition in decapod crustacean larvae

In meroplanktonic larvae, growth is accompanied by developmental changes in physiological, biochemical, morphological, behavioural, and ecological traits, and these patterns are further modified by variations in the physico-chemical environment. This paper reviews patterns of growth and chemical composition in planktotrophic marine decapod larvae developing under constant close to optimal conditions, as well as some alterations imposed on these patterns by nutritional, thermal, osmotic, or other stress. Different suboptimal conditions such as food limitation, unsuitable temperatures, or low salinity stress may exert similar bioenergetic effects which, in general, can be measured as a decline in the rates of development and growth or in changing proportions of chemical constituents of larval biomass. The fractions of carbon (c), total lipids, triacylglycerides (TAG), polyunsaturated fatty acids (PUFA), RNA, and ratios of carbon:nitrogen (C:N), lipid:protein, TAG: total polar lipid, and RNA;DNA have been used as chemical indicators of physiological condition. Quantitative relationships between elemental (C, N) and proximate biochemical fractions (lipid, protein) may vary with nutritional condition, developmental mode (planktotrophy vs. lecithotrophy), clade, and possibly, between field-caught and laboratory-reared larvae ("domestication effects"). Besides further comparative laboratory investigations, more field data are necessary to increase the realism of our models of larval growth and development in the Decapoda and other crustaceans