Aquatic Sciences Meeting, Albuquerque 2001

SS39 Evolution in Aquatic Environments (Spatial and Temporal Connections)

Date: Monday, February 12, 2001, Time: 4:30:00 PM

Location: Dona Ana

Twombly, S, , University of Rhode Island, Kingston, RI, USA, twombly@uri.edu

Tisch, N, , Cornell University, Ithaca, NY, USA, nt34@cornell.edu

QUANTITATIVE GENETICS OF GROWTH AND DEVELOPMENT IN A FRESHWATER COPEPOD

Although growth and development are important components of individual fitness, rates often differ substantially among individuals in any population. This variation can have both genetic and environmental bases. We raised full sibs from known parents of Diaptomus leptopus in order to quantify the amount of additive genetic variation present for several growth and developmental traits (heritability) and to determine the extent to which these traits are coupled (genetic correlations). We found significant heritability for developmental rates (age at metamorphosis, age at maturity), but not for growth. Age and size were correlated (negatively) at metamorphosis only, suggesting that metamorphosis disrupts the coupling between these two processes. We also found significant correlations between different ontogenetic stages for age only, which suggests that selection acts to minimize development times throughout the life cycle, irrespective of growth rates and body sizes. These quantitative genetic statistics closely parallel results from a previous study that showed fitness effects of development, but not of growth, in this species. We predict that selection in field situations will act on the genetic variation present to minimize developmental rates, but have little effect on body size.

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Aquatic Sciences Meeting, Albuquerque 2001

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