|SS1.03 Zooplankton Response to Climate Variability|
|Date: Monday, June 10, 2002|
|Time: 3:45:00 PM|
|Location: Lecture Theatre|
|Mitchell, S, E, Max Planck Institut of Limnology, Ploen, Germany, firstname.lastname@example.org|
|Lampert, W, , Max Planck Institute of Limnology, Ploen, Germany, email@example.com|
|Halves, J, , Max Planck Institute of Limnology, Ploen, Germany, |
|TEMPERATURE ADAPTATION IN DAPHNIA MAGNA: POSSIBLE REACTION TO A TEMPERATURE CHANGE|
|Clonal cladoceran populations may compensate slow temperature changes depending on the local genetic variability of temperature reaction norms. (1) If it is high, rare clones adapted to the new temperature conditions may become dominant. (2) If it is insufficient, but differentiation exists between different climatic localities, affected water bodies may be recolonized by better adapted clones.
We measured temperature reaction norms of D. magna clones either isolated from two ponds in northern Germany at different seasons or hatched from ephippia collected from diverse geographical locations in Europe. The reaction norms of all clones peaked at temperatures higher than normally experienced in the field. We found significant genotypic variation and G X E interactions without genetic correlations within all populations. However, the mean reaction norms for all periods and overall in the two neighboring pond populations were parallel, i.e., there was no seasonal temperature adaptation. Similarly, average reaction norms of geographically separated populations were parallel although southern populations had higher growth rates than northern populations. We conclude that D. magna populations contain sufficient within population genetic variation to cope with moderate temperature changes.