My work combines molecular genetic analyses with life history, behavioural, physiological, and morphological data collected in wild populations of various species to investigate the forces that may maintain additive genetic diversity in the wild.
My research focuses on two interlinked topics. First, I have been working on various aspects of sexual selection in a socially monogamous species with extra-pair paternity, the blue tit (parus caeruleus). Using long-term data on individual genetic diversity and extra-pair paternity in blue tits (Cyanistes caeruleus) from Vienna, Austria, we demonstrated that females may gain genetic benefits in terms of 'compatible genes' through extra-pair copulations. In socially monogamous birds where mate choice is restricted, extra-pair matings often provide the only opportunity to produce genetically superior offspring. We showed that the two types of genetic benefits, namely 'good genes' and 'compatible genes' can drive the evolution of multiple mate choice within the same system.
Second, I started to use quantitative genetic methods to study mechanisms that may maintain genetic variation in natural populations. Heritable genetic variation for fitness traits is a paradox finding, given our understanding of directional selection processes on such traits. Drosophila laboratory experiments suggested the existence of limits to the evolution of a single genetic optimum for males and females. Using an exceptional long-term data set on free-living red deer (Cervus elaphus) from the Isle of Rum, Scotland, we demonstrated the existence of sexually antagonistic fitness variation in a natural population. This study shows that the selective advantage of 'good genes' is gender-specific: good genes for males are not necessarily good genes for females. Currently, I aim at establishing a semi-natural population of harvest mice (Micromys minutus) to study population development over several generations, and to tackle questions on sexual selection and on the maintenance of genetic variability in this species.
Teixeira S, Foerster K, Bernasconi G, 2009. Evidence for inbreeding depression and post-pollination selection against inbreeding in the dioecious plant Silene latifolia. Heredity 102: 101-112.
Kempenaers B, Peters A & Foerster K, 2008. Individual variation in plasma testosterone levels - causes and consequences. Philosophical Transactions of the Royal Society London B 363: 1711-1723.
Foerster K, Coulson T, Sheldon BC, Pemberton JM, Clutton-Brock TH & Kruuk LEB, 2007. Sexually antagonistic genetic variation for fitness in red deer. Nature 447: 1107-1110.
Foerster K, Valcu M, Johnsen A & Kempenaers B, 2006. A spatial genetic structure and effects of relatedness on mate choice in a wild bird population. Molecular Ecology 15: 4555-4567.
Foerster K, Delhey K, Johnsen A, Lifjeld JT & Kempenaers B, 2003. Females increase offspring heterozygosity and fitness through extra-pair matings. Nature 425: 714-718.