Mitchell, S. E. Max-Planck Institute for Limnology, mitchell@mpil-ploen.mpg.de
Lampert, W. E. Max-Planck Institute for Limnology, lampert@mpil-ploen.mpg.de

 
TEMPERATURE REACTION NORMS FOR GROWTH RATES IN DAPHNIA MAGNA
 
Can the latitudinal distribution of a widespread zooplankton species tell us anything about temperature adaptation to localised climatic conditions? If so, one might expect an inverse relationship between latitude and the temperature where optimal growth is achieved. We tested this relationship using the cyclic parthenogen, Daphnia magna, that inhabits shallow ponds across a broad latitudinal range in Europe. Temperature reaction norms for somatic growth rate (g) were investigated for 64 ex-ephippial clones originating from eight European populations, ranging from Finland (60oN) to Southern Spain (37oN). Individuals were grown at six temperatures at 3oC intervals from 17-32oC. Preliminary data indicate that optimal growth rates occur between 23oC and 26oC, with very little survivorship at 32oC. Since Daphnia produce diapausing eggs, that hatch when growth conditions are favourable, one must consider not only latitude but the local seasonal phenology of population occurrence to elucidate temperature-dependent adaptation.
 
Day: Wednesday, Feb. 3
Time: 02:00 - 02:15pm
Location: Hilton of Santa Fe
 
Code: CS66WE0200H