dr.ir. JC (Bob) Douma

dr.ir. JC (Bob) Douma

Assistant professor

Plant-plant-pest interactions

My research is in the domain of plant-plant-pest interactions. I am interested in how plant-plant interactions are shaped by insects, and how plant communties are assembled. I want to unravel these processes and relationships through the application of models, field and greenhouse experiments and analysis of large datasets.

I love the application of novel statistical tools to answer intruiging ecological questions. For example, the application of structural equation modeling to describe relationships between variables or the use of generalized mixed effects models to analyse field experiments.

This research is funded through a VENI grant.

Current project: Exploiting your neighbours cry for help the role of herbivore induced plant volatiles in plant growth strategies

In my current project, I study the strategies of plants that receive (herbivore induced) plant volatile signals to maximise their performance in competition with other plants.

I use a combination of 3D modelling, evolutionary game theory and experiments to analyse benefits of growth versus defence responses. I will develop a detailed 3D model for plant growth and structural development under competition (e.g. for light) and herbivory. This model will be used as a game theoretical tool to identify plant strategies that provide competitive advantage when a neighbour has been attacked by herbivores.

Previous project Development of probabilistic pathways for plant pest introduction in the EU territory through non edible plant products or plants.

The aim of this project is to provide the European Food and Safety Authority (EFSA) with probabilistic models for quantitative pathway analysis of plant pest introduction for the EU territory through non-edible plant products or plants.

In this project, we provided a conceptualization of two types of pathway models. The individual based PM simulates an individual consignment (or a population of such consignment) by describing the stochastic change in the state of the individual consignment over time and space. The flow-based PM, simulates the flow of infested product over time and space, without distinguishing individual consignments. We show how these two conceptualisations are mathematically related, and present, as a show case, both models for cut flowers.

Second, we developed PMs for five product groups: round wood, sawn wood, cut flowers, plants for planting and seeds. For each product group we have developed a case-study (combination of product, origin and pest) to illustrate the use of the pathway models: (1) oak wood from the USA and Ceratocystis fagacearum, (2) Coniferous sawn wood from China and Bursaphelenchus xylophilus, (3) Cut orchids from Thailand and Thrips palmi, (4) Pot orchids from Thailand and Thrips palmi, and (5) Tomato seeds and Clavibacter michiganensis subsp. michiganensis from outside the European Union.

Third, we provided a practical guidance on i) how to develop a PM, ii) the application of PMs in @Risk (a plugin for MS Excel), and iii) application in R.

The full report can be downloaded from the EFSA website