On 5 February 2026, Marie Oltmersuccessfully defended her dissertation entitled: "The role of actors in policy processes towards policy mixes for sustainability transitions: An analysis of insect conservation policy in Germany". In her work, Marie combines findings from transition research with political science approaches and develops a concept in which she links policy process theories with policy mix approaches, thereby focussing more strongly on actors. Empirically, Marie analyses the development of biodiversity and insect conservation policy in Germany. We were particularly pleased that Prof Dr Karoline Rogge not only took on the second opinion, but also made the long journey to Oldenburg to be there. Many thanks to the entire commission for the constructive debate and congratulations to Dr Marie Oltmer!