Future food systems must provide more food produced on less land with fewer greenhouse gas emissions if the goal is to keep planetary boundaries within safe zones. The valorisation of agricultural and industrial by-products by insects is an increasingly investigated strategy, because it can help to address resource scarcities and related environmental issues. Thus, insects for food and feed have gained increasing attention as a sustainable protein production strategy in circular food systems lately. In this article, we provide an overview on by-products, which have already been fed to T. molitor (mealworms), a common edible insect species. In addition, we investigate other by-products in Austria, which can be suitable substrates for T. molitor farming. We also provide an overview and discuss different perspectives on T. molitor and link it with the circular economy concept. We identify several future research fields, such as more comprehensive feeding trials with other by-products, feeding trials with mealworms over several generations, and the development of a standardized framework for insect rearing trials. In addition, we argue that due to their ability to convert organic by-products from agricultural and industrial processes into biomass in an efficient way, T. molitor can contribute towards resource-efficient and circular food and feed production. However, several hurdles, such as legal frameworks, need to be adapted, and further research is needed to fully reap the benefits of mealworm farming.

Due to the current challenges of climate change, population growth in urban settlements and resource depletion, agri-food researchers have put an increasing emphasis on the sustainability transitions of food systems. In this regard, there has been an increasing interest in the local food supply of cities and their surrounding regions, as local food is considered to be a contributing factor toward more sustainable, resilient and just urban food systems. Based on this background, a roadmapping process was conducted to assess the status quo and to identify measures to enhance the local food supply in the city-region of Graz in Austria. We conducted semi-structured interviews with 47 stakeholders, analysed textual materials and calculated food carrying capacities. The obtained data served as input for a series of three workshops, where measures were derived. Our results suggest that cooperation among agri-food stakeholders should be facilitated by local decision makers in order to promote food from regional sources within the target area. Furthermore, smart technologies can help to scale-up local food supply schemes, and to track down food stocks and flows more efficiently. Besides, food policy councils and open food labs can help to incubate food product innovations and to support partnerships among agri-food stakeholders, including local small-scale farmers. In the future, engagement and empowerment processes with local food stakeholders should be addressed to enable transformational processes. Roadmaps can help to initiate such processes.