Community ecology of plant-insect interactions

Designing mixed cropping systems and transition paths towards sustainable ecology based agriculture (CropMix)

Pollination by insects is rewarded with floral nectar. However, as a nutrient-rich and well-protected environment, flower nectar also supports a diverse community of beneficial, commensal, and antagonistic microbes. These microorganisms influence the interaction between the plant and its pollinators, but also with nectar robbers and flower-feeding herbivores by altering the nutritional value and the chemical composition of the nectar. Despite the importance of pollination for seed production of many brassicaceous crops, little is known on the role of the nectar microbiome for plant fitness and seed set in these plants. Besides plant fitness, nectar microbes also impact pollinator health and thereby strongly influence the pollinator community beyond individual plant-pollinator interactions. The central questions of this PhD project are (I) does the microbiome in the flower nectar influences plant-pollinator interactions and plant fitness? (II) can specific microbes be used to improve seed set in brassicaceous crops as well as pollinator health?

Evolution of plant defence plasticity to multi-herbivore attack

Phylogenomics of plasticity in plant defence signalling

Versatile Aphids: the role of salivary components and the micriobiome on aphid-plant interactions

The goal is: to generate and bring together knowledge about the critical factors that contribute to more biodiversity in arable farming as a result of the application of various ecological structures and strip cropping. This knowledge together with experience of farmers is used to add indicators for biodiversity to the Biodiversity Monitor Arable Farming. Also a tool will be developed for farmers to make choices about which ecological structures they can add to their farms for more biodiversity and receiving good compensation.

Plant resistance to aphids in wild peppers

Crop diversity in space and time to enhance biocontrol of insect herbivores

Crop diversity in space and time supports effective plant trait combinations that reduce herbivory and pathogen attack

Evolution of growth-defence-reproduction tradeoffs to multi-herbivore attack in the Brassicaceae plant family

Discover the repertoire of plant defence plasticity to multi-herbivore attack and its phylogenetic relationship

We study the transition to sustainable ecology-based agriculture by using mixed-cropping systems that combine multiple crop species on a single field. Our team elucidates the ecological processes that make mixed cropping systems sustainably productive and we identify which socio-economic and societal or institutional factor need to be resolved to overcome the lock-in in current conventional farming systems. To allow a broad spectrum of farmers, consumers and stakeholders to reach transition goals, we embrace variation in transition paths. We explicitly compare how existing international value chains require adjustments as well as how new short and local value chains can emerge.

Strip cropping is an accessible crop diversification practice for farmers as strip width can be chosen to fit the working width of available machinery. The strip cropping experiments at WUR have shown positive results for biodiversity and pest and disease control. However, what is the effect of strip cropping on yield? Positive effects on yield might be an important incentive for farmers to adopt strip cropping. Furthermore, what happens when a farmer starts implementing strip cropping themselves? Do we see the same results as in our scientific experiments?

Plants are in constant battle with insect pests like caterpillars. Plants detect the presence of these caterpillars through cues like their oral secretions. As a response, plants then activate a cascade of defensive mechanisms. These defensive mechanisms can, on their turn, influence other insects that live on the plant. When caterpillars are infected with a parasitoid virus after parasitation by a parasitoid wasp, the composition of the caterpillar's oral secretions is changed. Because of this change in oral secretion composition, the plant's defensive response to infected caterpillars is altered in such a way that another important caterpillar pest is repelled from the plant. In this project, I want to research how this parasitoid virus influences the plant response. With this knowledge, plants may eventually be developed that are more resistant to insect pests.