CS39A Zooplankton - Feeding, Reproduction, Growth and Molecular Diversity
Date: Tuesday, June 11, 2002
Time: 2:30:00 PM
Location: View Royal
 
JankowskiT, University of Konstanz, Konstanz, Germany, thomas.jankowski@uni-konstanz.de
Straile, D, , University of Konstanz, Konstanz, Germany, dietmar.straile@uni-konstanz.de
 
SEXUAL REPRODUCTION AND GENETIC ARCHITECTURE IN A DAPHNIA HYBRID SYSTEM
image
We investigated the Daphnia hyalina-galeata hybrid system from Lake Constance in order to study the consequences of sexual reproductive behavior (timing and frequency) for the genetic architecture within this hybrid system. D. hyalina rich and D. galeata rich genotypes differed strongly in sexual reproductive behavior: D. hyalina rich genotypes overwintered in the plankton, whereas D. galeata rich genotypes overwintered as resting eggs. Consequently, D. galeata rich genotypes investigated more into sexual reproduction as D. hyalina rich genotypes. Higher frequency of sexual reproduction was associated with a higher genetic diversity of D. galeata rich genotypes as compared to D. hyalina rich genotypes. Fst values suggest clonal selection during summer and autumn against D. galeata rich genotypes, whereas D. hyalina rich genotypes increased in relativ importance towards autumn and winter. This corresponds with sexual production of D. galeata rich genotypes at their maximum abundance shortly after the phytoplankton bloom in late spring, and sexual reproduction of D. hyalina rich genotypes in autumn. Together, these findings suggest different microevolutionary trajectories of the parental species, which will be discussed in light of the ongoing reoligotrophication process of Lake Constance.