Spaak, P. EAWAG / ETH, spaak@eawag.ch
Boersma, M. Max-Planck-Institut für Limnologie, boersma@mpil-ploen.mpg.de

 
PREDATOR INDUCED DIFFERENTIATION IN LIFE HISTORY AND BEHAVIOUR OF DAPHNIA: THE MAINTENANCE OF CLONAL DIVERSITY IN A HYBRID SPECIES COMPLEX
 
Different Daphnia species and their hybrids coexist in many lakes. We studied the potential influence of predatory fish on the maintenance of these species complexes. In a life history experiment with 20 Daphnia clones, belonging to 5 hybrid and parental taxa of the Daphnia galeata complex we investigated the effect of fish kairomones, and observed that the larger taxa reacted more to the presence of these kairomones than the smaller ones. We used the same clones in a competition experiment in two large-scale indoor containers, the plankton towers in Plön, and varied the presence of fish and kairomones. We observed clonal variation for Diel Vertical Migration. Without fish, two clones belonging to the largest taxa (D. galeata and D. galeata x hyalina) were numerically dominant. However, when fish was present relative densities of smaller D. cucullata x galeata clones were highest. The results of these experiments with respect to overall taxon success were in concordance with each other, but we could not predict the individual clonal success from the life-history experiment only. We conclude that both life-history and behavioural data are needed to understand the success of individual clones in a predatory environment. The relevance of our results for field situations is discussed.
 
Day: Thursday, Feb. 4
Time: 11:45 - 12:00pm
Location: Hilton of Santa Fe
 
Code: SS16TH1145H