Das Projekt "Evolutionary Conflicts and their Impact on Speciation" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Institut für Integrative Biologie durchgeführt. Within the general framework of evolutionary theory, I am particularly interested in sexual selection and evolutionary conflicts within and between species (sexual and host-parasite conflicts) as potential drivers of speciation. Reproductive barriers between populations are of crucial importance as they can help explain how new species are formed and what factors encourage or constrain biodiversity. Reproductive traits are known to be susceptible to very rapid evolutionary change yet the exact traits responsible for reproductive isolation generally remain unclear. I aim to identify such traits and understand how they diverge and affect reproductive barriers between populations in Tribolium flour beetles (important pests of stored products and genetically tractable model organisms). I will mainly use a powerful long-term 'experimental evolution' approach to examine whether sexual selection generates greater differences in reproductive traits and accelerates reproductive isolation. To do this, I will be using different populations maintained under different levels of sexual selection (through variation in the intensity of competition between males to produce offspring). In addition to detailed experimental studies of a range of reproductive characters and the impact of endosymbionts on host reproduction, I will run a combined experimental evolution experiment incorporating different levels of sexual selection and status of infection (infected vs. uninfected). This will enable me to judge how both sexual selection and reproductive parasites (such as the bacterial endosymbiont Wolbachia) impact on speciation. Despite strong theoretical support, the importance of sexual selection and evolutionary conflicts as speciation engines remains controversial and hence generates intense debate. This research aims to establish whether these forces can act singly or combined to accelerate speciation (and ultimately generate biodiversity) and their overall and relative importance as engines of speciation. This will be of particular interest to scientists working in the fields of evolutionary biology and behavioural ecology, but also to ecologists, reproductive biologists, and conservation biologists. Because Tribolium beetles are agricultural pests of considerable economic importance, results will also be relevant to more applied researchers. Moreover, as endosymbionts could have potential applications as biocontrol agents for pests or insect vectors of disease, it is critical that detailed knowledge of consequences for the host of infection with the symbiont is available.
Das Projekt "Evolutionary Conflicts and their Impact on Speciation (follow-up)" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Institut für Integrative Biologie durchgeführt. In addition to recognizing natural selection as a universal mechanism in evolution, Darwin also saw the importance of sexual selection, yet the two have been traditionally treated largely in isolation. Here I propose to apply experimental evolution (exposing experimental populations to controlled specific selective pressures over many generations in the laboratory) to the ideally suited model system Tribolium castaneum to explore how these evolutionary forces interact and impact on the key processes underlying biodiversity. Understanding how these fundamental forces, singly and in conjunction, influence species divergence remains a major challenge in evolutionary biology. Participation of sexual selection in driving speciation is supported by substantial theoretical evidence. Theory further suggests that evolutionary conflicts (such as between the sexes or between host and parasite) might also accelerate extinction. Additional complexity is introduced by including the environmental context, linking back to natural selection. Direct experimental tests of the above concepts are essentially lacking. I will explicitly target this gap by exploiting powerful experimental evolution, incorporating the interplay between sexual selection intensity, host-parasite conflict, and adaptation to increasing temperature. Projects will assess how selection under evolutionary conflict and environmental change affects both adaptation and extinction rates, aiming to elucidate underlying mechanisms. Additionally, building on clear phenotypic divergence in key traits across experimental evolution lines, I will significantly expand on previous work by assessing patterns of divergence in gene expression, concentrating on target genes associated with reproduction, immunity and heat shock. This research will be of particular interest to scientists working in the fields of evolutionary biology and behavioural ecology, but also to ecologists, reproductive biologists, and conservation biologists. As Tribolium beetles are widespread agricultural pests, results will also be relevant to more applied researchers.