A range of anthropogenic stresses are threatening biodiversity across large swathes of the biosphere, and these are having negative effects on the functioning of ecosystems and the communities that are embedded in them. However, at present, our understanding of the effects of various ecological stresses on species interactions in communities is quite rudimentary.
In order to unravel the many complex processes involved in elucidating the effects of individual and synergized aspects of global change requires a more holistic approach, covering individual interactions (i.e. behaviour, ontogeny, trophic interactions) to such emergent processes occurring at much larger scales such as system assembly, productivity and resilience. My research focuses primarily on mechanisms, studying interactions occurring at smaller scales, and using these to bridge the results research by colleagues working at larger scales.
In this regard, my research focuses on trophic interactions involving plants, insect herbivores and their natural enemies including predators and parasitoids, and in turn hyperparasitoids. I am especially interested how trophic interactions are affected by both biotic and abiotic factors, and in this context much of my research has been based on studies involving parasitic wasps and their insect herbivore hosts. A key part of my work involves how differences in life-history traits in plants and insects affect their ability to exploit changing habitats and dynamic shifts in resources. My research looks intimately at genetic variation in plant-related traits, such as life cycles, primary and secondary chemistry, and seasonal phenology and how these parameters affect host-finding behaviour and performance in insect herbivores and their antagonists up the food chain. The insects, in turn, exhibit differences in various eco-physiological traits, which are a key component of my research. I am also interested in more intimate aspects of life-history evolution involving plant-herbivore and herbivore-parasitoid associations.
Model plant species involved in my research include species in the cabbage and mustard family (Brassicaceae) which includes the model plant in genomics, Arabidopsis thaliana as well as a wide range of crop plants. These plants often exhibit profound intra- and inter-specific differences in secondary (defense) chemistry, and understanding the factors accounting for this variation is an area in which some of my research is focused. I am also interested in two main areas of global change research, plant invasions and climate change-related effects. One of the model plants used in my research, Bunias orientalis, the warty cabbage, is an invader from western Asia. Other plant species I work with include milkweeds (Asclepias spp.) and primroses (Oenothera spp). My research also involves links between above- and below-ground trophic interactions, again focusing on genetic variation in plant defense traits in the shoot and root tissues and reciprocal effects on soil and above-ground invertebrates.
I have a number of national and international collaborations involving various facets of my research. These include Paul Ode (University of Colorado, USA), Anurag Agrawal (Cornell University, USA), Erika-Hersch Green (Michigan Technological University, USA), Mark Jervis (Cardiff University, UK), Heiko Vogel (Max Planck Institute, Jena, Germany), Saskya van Nouhuys (University of Helsinki, Finland) and Toshiharu Tanaka (Nagoya University, Japan). In the Netherlands, collaborators include Jacintha Ellers (VU University, Amsterdam), Rieta Gols and Erik Poelman (Wageningen University) and Nicole van Dam (Radboud University, Nijmegen).
Current group-members:
