Bram Kuiper: "The strength of sexual selection in hermaphrodites versus gonochorists: a theoretical analysis"
Summary: Although it is often argued that sexual selection is weaker in simultaneous hermaphrodites than in separate-sexed organisms (gonochorists), this argument has received surprisingly little formal investigation. To bridge this gap, I extend standard models of sexual selection to hermaphrodites and incorporate aspects that are characteristic of hermaphroditic lifestyles, such as flexible sex allocation and reciprocal mating. While flexible sex allocation appears to diminish the strength of sexual selection in hermaphrodites, reciprocal mate choice results in sexual selection being as strong as in gonochorists. I conclude (and quantify) that sexual selection is generally weaker in simultaneous hermaphrodites, but that certain mate choice scenarios provide intriguing exceptions. (Einladung K. Reinhold)
Wie Nemo tatsächlich heimfinden könnte: Geruchsorientierung und Verwandtenerkennung bei Korallenfischen und anderen
In einem langjährigen Projekt am Great Barrier Reef untersuchen wir das Ausbreitungsverhalten von Korallenriff-Fischen und wie sie als Larve nach wochenlanger Wanderung im offenen Ozean wieder an ein Riff finden. Dabei spielen Gerüche des Riffs und der eigenen Population eine wichtige Rolle.
Andrea Thiel, Bremen (Einladung: Kolss) verschoben vom 23.06.2010 auf den 07.07.2010
Abstract: Many parasitoids live in environments that vary in resource availability and quality within and between generations. The use of information to adapt one’s behavior to the current environment is a key feature under such circumstances, and parasitic wasps are excellent model systems to study such learning and information use. If related species are tested under similar conditions, this allows for the analysis of within- and between-species variability, the effect of natural selection in a typical environment, the current physiological status, and previous experience of the individual. This holds for host habitat and host location as well as for host choice and search time allocation. I will briefly review patterns of learning and memory, of information use and updating mechanisms described so far for parasitoid wasps and then show from experimental data that cognitive processes and information use themselves are under strong selective pressure and thus optimized by parasitic wasps.