Physiological Variation Among Clonal Genotypes in the Sea Anemone Haliplanella lineata: Growth and Biochemical Content.

We have explored physiological variability among clonal genotypes from a single population of the sea anemone Haliplanella lineata located at Indian Field Creek, Virginia. Information about the correlation between physiological variability and genetic differences may provide a foundation for a mechanistic understanding of the breadth of adaptation of individual genotypes (i.e., the nature of "general purpose genotypes") and of the concept of localized adaptation in clonal anemones. Anemones from three clones (A, B, C) were fed measured rations of adult Artemia, after which growth, absorption efficiency, and net growth efficiency were determined. Biochemical constituents were measured in the tissue of this group of anemones as well as in the tissue of anemones from the same clones that had fed ad libitum on Artemia nauplii. Anemones from the different clones did not differ significantly in growth, or gravimetric absorption or growth efficiencies, but significant differences were found in biochemical composition. Regardless of feeding regime and diet composition, clone B anemones consistently had lower tissue averages of triacylglycerols, fatty acids, sterol and wax esters, glycerol ethers, and carbohydrates than did clone A and clone C anemones. As a result of differences in the carbohydrate and lipid constituents, the energetic content of tissues from clone B anemones that had been fed rations was significantly lower than the energetic content of tissues of anemones from clone C. This clonal pattern in biochemical composition and energetic content may be due to differences in substrate absorption among anemones from the different clones, to differences in metabolic rate, or to a combination of both. Because anemones from this population may encyst in mucus and stop feeding when water temperatures are less than 10{deg}C, the genotypic differences in storage lipids and carbohydrate may have implications for the winter survivorship of clone B anemones in this population.