LAUSR

Abstract The harpacticoid copepod Nitocra spinipes is a commonly used test species in ecotoxicological studies and subject of multiple international testing guidelines. While we strive for a better understanding of toxicant-induced effects in this species, physiological models rooted in the Dynamic Energy Budget (DEB) theory can help to explain such effects on the level of energy allocations within the organism. In previous works that aimed to capture the copepod life history in a DEB model, diverging assumptions on the growth pattern of copepods were made. While some authors presumed von Bertalanffy growth, others presumed an upcurving in length versus time due to metabolic acceleration. In this study we parametrized the two typified DEB models “abp” (metabolic acceleration from birth to puberty) and “sbp” (standard von Bertalanffy growth from birth to puberty) on life history data of N. spinipes. Besides using data from literature, we also measured additional length-at-time data to aid the parameter estimation. As the body proportions of N. spinipes changed continuously throughout its development, we used the square root of the top view area as a length measure to scale with the cube root of structural volume in length-to-volume conversions. Experimental data were predicted well with both models according to goodness of fit criteria. Despite a slightly better data fit in abp, we cannot rule out sbp as implausible. Overall, we expect both models to perform equally well in future applications. More detailed data on N. spinipes and closely related species are needed to support or reject the presumption of metabolic acceleration in the life history of copepods.