2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

often served as a model organism in the study of how ecological context affects
survival and fertility trajectories. Here, focus is given to the both ends of life history.
First, recent results on how environmental interventions affect the rates of Daphnia
aging are discussed. Second, an undergoing project is presented, in which Daphnia is
used in experiments aimed at explaining the patterns of developmental mortality via
linking age-specific mortality to age-specific transcription.
S�3 Justyna Wolinska, Sabine Gießler R513 / 13:45
Coevolution between Daphnia and their parasites: a new method to capture
genetic changes in parasite population
Authors: Justyna Wolinska 1 , Sabine Gießler 1
Affiliation: 1 Ludwig-Maximilians-Universität München
Many Daphnia species are infected by tiny microbial parasites, potentially resulting in
dynamic host-parasite coevolution between the two players. So far, however, the
genetic changes have been followed only for one of the players, the host. It‘s high
time to shed light on a so far hidden part of coevolutionary process: the genetic
changes within parasite populations. Using recently developed molecular markers,
ITS sequence data, we captured the spatial and temporal dynamics in population
structure of two different parasite species infecting Daphnia hosts. Furthermore we
relate the spatial structure of parasite populations with their most likely dispersal
mode and discuss how parasite life cycle variation can shape coevolution. Moreover,
we will now be able to use genetic information from both players at the same time.
This opens tremendous possibilities for both field and experimental studies.
S�4 Olivia Hesse R513 / 14:00
The impact of anthropogenetic stressors and simultaneous parasite infection on
Daphnia
Authors: Olivia Hesse 1 , Justyna Wolinska 1 , Christian Laforsch 1
Affiliation: 1 Ludwig-Maximilians-Universität München
In most studies evaluating the potential danger of anthropogenetic chemicals, the
target animal is exposed to the substance under otherwise ideal conditions.
However, in nature, organisms are often exposed to other environmental stressors
such as parasites. The impact of anthropogenetic substances might considerably
differ when the organism is additionally infected. To test this, we conducted several
experiments where we exposed Daphnia magna to environmentally relevant
concentrations of pesticides (diazinone, imidacloprid) or the pharmaceutical
carbamazepine and additionally infected them with the parasite Metschnikowia sp.
The pharmaceutical carbamazepine and the pesticide diazinone significantly
increased the susceptibility of Daphnia to the parasite. Moreover, when exposed to
the pesticide imidacloprid, the infection rate, but also life span was reduced. Our
results show that the effect of anthropogenetic substances on non target organisms
can be stronger if these organisms are additionally exposed to parasites. Hence,
studies testing the effects of toxic compounds may underestimate the environmental
impact of these chemicals.
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