Susi Zajitschek
Former Post Doc
Generally, my research focuses on evolutionary biology and encompasses reproductive biology, behavioural ecology and molecular genetics as well as the study of life history.
I have a special interest in postcopulatory processes, and have recently investigated the adaptive ability of sperm on an intra-individual level with Simone Immler at Uppsala University, and will be extending my sperm expertise to the species level here in the Manier Lab, were we will investigate the evolution of sperm length, and its adaptive significance. In Drosophila species, this is particularly exciting, as there is a huge variation across closely related species, ranging from relatively short sperm in D. melanogaster (1.8mm) to giant sperm in D. bifurca (58mm).
The role of epigenetic effects in adapting to changing environments
My research on zebrafish (Danio rerio) in the Immler lab (http://www.ebc.uu.se/Research/IEG/evbiol/research/Immler/) at the EBC at Uppsala University (Sweden) investigated the interplay of haploid selection, phenotypic plasticity in sperm and epigenetic inheritance. Drawing on the current paradigm shift in evolutionary ecology, which combines genetic and non-genetic transgenerational inheritance mechanisms, a particular focus of this research was to study how variation in not only in male reproductive traits but also in paternal social environment mediates reproductive success. Specifically, I investigated the role of social environment on multiple levels, looking at fitness differences of offspring, which are presumably transmitted to the offspring via epigenetic modifications in the paternal ejaculate.
Life history and ageing
How life history strategies, and specifically age-related processes, change in relation to dietary composition and vary between the sexes, has been investigated in detail in collaboration with Dr. Felix Zajitschek http://felixzajitschek.wordpress.com/professional/, using Australian field crickets (Teleogryllus commodus) and Drosophila melanogaster. In field crickets, we investigated sex-specific mortality in the field and heritability and genetic correlations of sexually selected traits using a large-scale quantitative breeding design. The work on sex-specific patterns of ageing in connection with different dietary components has introduced me to Drosophila culturing and experimentation.
The interaction between population structure and behavior: studying dispersal
During my postdoc at the CNRS in Moulis (France) (http://www.ecoex-moulis.cnrs.fr/spip.php?article200) I primarily concentrated drawing the link between individual behaviour and environmental common lizards (Zootoca [formerly Lacerta] vivipara). We found that the propensity to initiate movement is critically dependent on the type of substrate, the level of humidity, and the opportunity to thermoregulate. However, there are also indications that the social environment influences dispersal not only in respect to inbreeding and competition avoidance by the dispersing individuals, but that in the wild siblings may aim to facilitate the risky dispersal process for each other.
In addition, large scale experiments in a semi-natural Metatron, a unique system of interconnected population cages, have allowed me to study the complex interactions of individual behaviour and personality, morphology, and the role of relatedness within released population groups.
Linking physiology to performance
How organisms respond to environmental factors is not only defined by behavioural characters, but to a large degree also by physiological factors. Studying underlying physiological mechanisms is vital for our understanding of phenotypic variation in traits and their evolutionary correlations. So during the time at the CNRS I have also investigated the role of thermoregulation on locomotor performance in European wall lizards (Podarcis muralis), finding a potential trade-off for red ornamentation in males, which may help explain the maintenance of the colour polymorphism in this species.
Inbreeding avoidance: precopulatory mechanisms to prevent inbreeding depression
During my PhD in the Brooks Lab (http://www.eerc.unsw.edu.au/rob-brooks) at the UNSW in Sydney, I investigated female mating behavior with a special focus on mechanisms related to potentially avoid inbreeding. Extending the field of sexual selection beyond pre-copulatory behavior, I also looked at processes happening at the postcopulatory level. I investigated findings on the negative effects of inbreeding on sperm quantity as well as inbreeding depression in sperm competition as revealed using artificial insemination techniques.
In a recent collaboration with Alexander Kotrschal (http://www.ebc.uu.se/Research/IEG/zooeko/People/Alexander_Kotrschal/?languageId=1) and Niclas Kolm (http://www.zoologi.su.se/about/staff/person.php?suuid=nkolm) at Uppsala University, I have returned to the investigation of guppy sperm. Specifically, I investigated potential trade-offs in gut mass and sperm production in connection to growing larger brains.
The Bombina hybrid zone
During my Masters studies at LMU in Munich (Germany), I worked in the lab of Beate Nürnberger http://www.evolutionary-ecology.bio.lmu.de/people/formermembers/nuernberger/index.html
In a stable hybrid zone of two species of fire-bellied toads (Bombina bombina / B. variegata) we found significant variation in the potential for thermal adaptation in tadpoles of the two source species, providing an ecological explanation for differential resource use.
Former Post Doc
Generally, my research focuses on evolutionary biology and encompasses reproductive biology, behavioural ecology and molecular genetics as well as the study of life history.
I have a special interest in postcopulatory processes, and have recently investigated the adaptive ability of sperm on an intra-individual level with Simone Immler at Uppsala University, and will be extending my sperm expertise to the species level here in the Manier Lab, were we will investigate the evolution of sperm length, and its adaptive significance. In Drosophila species, this is particularly exciting, as there is a huge variation across closely related species, ranging from relatively short sperm in D. melanogaster (1.8mm) to giant sperm in D. bifurca (58mm).
The role of epigenetic effects in adapting to changing environments
My research on zebrafish (Danio rerio) in the Immler lab (http://www.ebc.uu.se/Research/IEG/evbiol/research/Immler/) at the EBC at Uppsala University (Sweden) investigated the interplay of haploid selection, phenotypic plasticity in sperm and epigenetic inheritance. Drawing on the current paradigm shift in evolutionary ecology, which combines genetic and non-genetic transgenerational inheritance mechanisms, a particular focus of this research was to study how variation in not only in male reproductive traits but also in paternal social environment mediates reproductive success. Specifically, I investigated the role of social environment on multiple levels, looking at fitness differences of offspring, which are presumably transmitted to the offspring via epigenetic modifications in the paternal ejaculate.
Life history and ageing
How life history strategies, and specifically age-related processes, change in relation to dietary composition and vary between the sexes, has been investigated in detail in collaboration with Dr. Felix Zajitschek http://felixzajitschek.wordpress.com/professional/, using Australian field crickets (Teleogryllus commodus) and Drosophila melanogaster. In field crickets, we investigated sex-specific mortality in the field and heritability and genetic correlations of sexually selected traits using a large-scale quantitative breeding design. The work on sex-specific patterns of ageing in connection with different dietary components has introduced me to Drosophila culturing and experimentation.
The interaction between population structure and behavior: studying dispersal
During my postdoc at the CNRS in Moulis (France) (http://www.ecoex-moulis.cnrs.fr/spip.php?article200) I primarily concentrated drawing the link between individual behaviour and environmental common lizards (Zootoca [formerly Lacerta] vivipara). We found that the propensity to initiate movement is critically dependent on the type of substrate, the level of humidity, and the opportunity to thermoregulate. However, there are also indications that the social environment influences dispersal not only in respect to inbreeding and competition avoidance by the dispersing individuals, but that in the wild siblings may aim to facilitate the risky dispersal process for each other.
In addition, large scale experiments in a semi-natural Metatron, a unique system of interconnected population cages, have allowed me to study the complex interactions of individual behaviour and personality, morphology, and the role of relatedness within released population groups.
Linking physiology to performance
How organisms respond to environmental factors is not only defined by behavioural characters, but to a large degree also by physiological factors. Studying underlying physiological mechanisms is vital for our understanding of phenotypic variation in traits and their evolutionary correlations. So during the time at the CNRS I have also investigated the role of thermoregulation on locomotor performance in European wall lizards (Podarcis muralis), finding a potential trade-off for red ornamentation in males, which may help explain the maintenance of the colour polymorphism in this species.
Inbreeding avoidance: precopulatory mechanisms to prevent inbreeding depression
During my PhD in the Brooks Lab (http://www.eerc.unsw.edu.au/rob-brooks) at the UNSW in Sydney, I investigated female mating behavior with a special focus on mechanisms related to potentially avoid inbreeding. Extending the field of sexual selection beyond pre-copulatory behavior, I also looked at processes happening at the postcopulatory level. I investigated findings on the negative effects of inbreeding on sperm quantity as well as inbreeding depression in sperm competition as revealed using artificial insemination techniques.
In a recent collaboration with Alexander Kotrschal (http://www.ebc.uu.se/Research/IEG/zooeko/People/Alexander_Kotrschal/?languageId=1) and Niclas Kolm (http://www.zoologi.su.se/about/staff/person.php?suuid=nkolm) at Uppsala University, I have returned to the investigation of guppy sperm. Specifically, I investigated potential trade-offs in gut mass and sperm production in connection to growing larger brains.
The Bombina hybrid zone
During my Masters studies at LMU in Munich (Germany), I worked in the lab of Beate Nürnberger http://www.evolutionary-ecology.bio.lmu.de/people/formermembers/nuernberger/index.html
In a stable hybrid zone of two species of fire-bellied toads (Bombina bombina / B. variegata) we found significant variation in the potential for thermal adaptation in tadpoles of the two source species, providing an ecological explanation for differential resource use.