2020: Best Master Thesis

Levke Valena Höche's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Christian-Albrechts-Universität zu Kiel in the year 2020.

Title: The combined effects of population origin and inbreeding on plant traits attracting pollinating insects

Inbreeding can have a negative impact on floral scent production and spatial flower traits. The magnitude of this effect strongly depends on the sex of plant individuals and the geographic origin of a population.

The attractiveness of a flower towards pollinators is determined by a combination of spatial and olfactory traits. Inbreeding can negatively impact these traits, and its effect can vary within a population between male and female plants, and among populations from different geographical origins.

We recorded differences in spatial and olfactory floral traits in outcrossed and inbred, female and male individuals of the dioecious plant Silene latifolia from eight European and eight North American populations. Additionally, visitation rates by crepuscular pollinators were quantified.

Inbreeding reduced the number and size of the flowers as well as the amount of lilac aldehydes that are essential for chemical communication with crepuscular moths. This effect was partially more pronounced in female than male individuals and varied between populations of different origins. However, this effect was not reflected in the pollinator visitation rates, which had only been investigated during a small timeframe in late summer for logistical reasons. Our results support that inbreeding has the potential to lessen the attractivity of a flower towards pollinating insects, and that sex-specific selection and the evolutionary history of a population shape the underlying genetic architecture.

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Levke Valena Höche conducted this work at the Institute for Ecosystem Research / Department Geobotany, supervised by Dr. Karin Schrieber.