WHAT ARE THE LONG-TERM CONSEQUENCE OF SOCIAL EXPERIENCES EARLY IN LIFE ?

Do parents prepare their offspring already before birth for their future environment ?

How do conflict & cooperation between parents and offspring shape interactions ?

How are early-life influences modified by experiences later in life ?

What are the hormonal, neural and genetic mechanisms of social interactions ?

        Zebra finch pair with young

Freshly hatched young begging

In general these questions address how parents may prepare offspring for their future by influencing early development, especially the prenatal environment, how family members affect each other, in particular the question to what extent parent and offspring control offspring development and who bears the costs or reaps the benefits of the mutual interactions within the family.

I also want to investigate theoretically how those interactions may be important for evolution. We usually consider that evolution optimizes how the genetic program of an individual interacts with the environment to ensure its survival and reproduction. It is much less well studied how evolution works if part of an individual's environment is shaped by its parents and siblings which partly carry the same genes and whose survival and reproduction is also optimized by selection. 

Social behaviour is one of the most attractive and fascinating topics in biology. I am interested both in the mechanisms and the function of social interactions.

Currently I am involved in a research project on the effect of the social environment during adolescence on behaviour of zebra finches later in life, part of a larger research program on reduction of phenotypic plasticity by early experience.

Before Bielefeld I worked in Cambridge, Groningen & Vienna on mechanism & function of hormone-mediated maternal effects, during my PhD thesis in Groningen on sex allocation in zebra finches and on hormone-mediated maternal effects in different species and before that at the German Primate Center in Göttingen on the behavioural endocrinology of female dominance in ring-tailed lemurs.

                     Ring-tailed lemurs

                Male zebra finch

              Song spectrogram

MATERNAL EFFECTS

2. Mechanism of hormone-mediated maternal effects

In collaboration with Erich Möstl and Sophie Rettenbacher at the University of Vienna and Ton Groothuis at the University of Groningen, I investigate the mechanisms of hormone-mediated maternal effects:
Can mothers independently regulate hormone secretion into the plasma and into the egg?
This is important since otherwise the effects of hormones on mother and offspring cannot evolve independently.
Second, can offspring regulate their response to the hormones? This might offspring them to avoid possible negative influences of the hormones on their development.
I also collaborated with Terry Burke and Gavin Hinten from Sheffield University in a project on the effects of maternal hormones on gene activity.

Various projects on avian yolk hormones
I was involved in projects on a range of species (pheasants, great-tits, blue-tits, pigeons, ostriches, chicken) especially by measuring or advising on the measurement of yolk hormones at the endocrine facilities at Groningen University.

Injection of zebra finch egg with testosterone

Chicken egg with embryo

Sex Allocation

I studied the effects of male attractiveness, food quality and female hormonal status on offspring sex-ratios and the sex-specific effects of yolk hormone on offspring development.
In a collaboration between Tim Fawcett and myself at Groningen University, Klaudia Witte in Bielefeld and Richard Zann in Melbourne we tried to replicate the influential study by Nancy Burley reporting an effect of the colouration of the leg-band of zebra finches on attractivenss of males and the sex-ratio of the offspring. Thanks to microsatellite primers provided by Wolfgang Forstmeier from Seewiesen we can now also analyse the genetic paternity of surviving and dead offspring to get a complete idea of primary and secondary sex-ratios produced by red-, green-, and orange-banded males.

I also was involved in the analysis of offspring sex ratios in relation to the social environment in guinea pigs, a study by the group of Norbert Sachser at Münster University.

BEHAVIOURAL ENDOCRINOLOGY

Female dominance in Lemur catta

Female dominance in ring-tailed lemurs may be linked to higher androgen levels. Observations during and outside the mating season and hormone measurements in faeces and saliva did not show higher androgen levels in females than in males, but the normal mammalian pattern. Observations were performed in two groups of lemurs in the zoo Hellabrunn in Munich and the Parque Zoologique de Thoiry close to Paris; analyses of androgens were done at the German Primate Center

Spotted hyaenas are the most prominent example for a species with female dominance. At the University of Berkeley, I worked on setting up a method to measure reproductive hormones in the field from faecal samples with Laurence Frank at the Field Station for Behavioural Research and Bill Lasley at the Institute for Toxicology and Environmental Health.

The brain is the most important organ regulating behaviour and physiology in interaction with the hormonal system. At the Centre for Integrative Physiology (Edinburgh) I was involved in a project investigating the control of growth-hormone release.

With respect to the mechanisms of hormone-mediated maternal effects, as part of an experiment with my colleague Claudio Carere in Groningen, the effects of yolk hormones on androgen receptors in the brains of developing zebra finches were analyzed in a pilot study in the group of Manfred Gahr at the Max-Planck-Institute in Seewiesen.

Teaching