Erik Poelman's research

Erik Poelman's research focuses on the mechanisms and community-wide consequences of the induced responses of plants to herbivore damage.

Research

In particular, I am interested in how plant responses to early season herbivores affect the subsequent colonization of plants by other arthropod species and thereby directly and indirectly mediate plant fitness consequences. I focus on plant- and other trait-mediated interactions among herbivores, parasitoids and hyperparasitoids. My work includes large manipulative field assays on insect communities associated with Brassica plants, field and laboratory assays on insect performance and behaviour. I am using molecular and chemical analysis to understand the underlying mechanisms of plant-mediated species interactions. My vision is that these indirect plant-mediated species interactions are an important factor in structuring insect communities, affect plant fitness and thereby consequentially are important in selection on plant traits. Currently, I am leading three projects dealing with the diverse arthropod community of Brassica nigra and Brassica oleracea in which we study the complex interactions between plants and their entire insect community, combining an ecological, genomic and metabolomic approach. 

Fitness consequences of plant-mediated community structure: Plants respond to herbivore attack by altering their phenotype to enhance resistance against the current attacker. However, the induced phenotype will also alter the plants interaction with other community members including herbivores, predators and pollinators. My work focuses on how early-season herbivores of Brassica plants shape the arthropod community that is subsequently colonizing the plant and whether thereby plants are affected in their fitness. I am using a combined approach of field ecology, laboratory studies on insect behaviour, and plant physiology including gene transcription and plant chemistry to study the plasticity of plant phenotypes and their interaction with the insect community.

Ecogenomics of indirect plant-mediated interactions in food webs up to the fourth trophic level: To understand how organisms at different trophic levels in a community interact with each other, I am studying a model system covering the four trophic level backbone of an insect community, using ~omics tools. The trophic backbone consists of Brassica plants, caterpillars of Pieris butterflies, its parasitoids and hyperparasitoids. With transcriptomics, I study the responses of plants to herbivores. Metabolomics is used to understand how parasitoids that lay their eggs inside herbivores affect the herbivore‚Äôs physiology (such as its regurgitant composition) and behaviour, and thus interaction with the plant. The interaction of parasitized herbivores with the plant affects performance of other herbivores or parasitoids that feed on this plant and affects behaviour of community members on different trophic levels      

Plant-mediated effects on parasitoid co-existence: Herbivores are often attacked by multiple parasitoid species that thereby are in extrinsic and/or intrinsic competition for hosts. My work aims at understanding which factors mediate the co-existence of these parasitoid species. An important aspect is that host herbivores occur on plants that are attacked by a suit of non-host herbivores. I study how the presence of non-host herbivores affects parasitoid foraging in terms of host location based on herbivore induced plant volatiles and decisions by parasitoids when foraging for herbivores on the plant. Plant quality and induced responses by host and non-host herbivores play an important role in host location by parasitoids and the sheer presence of non-host herbivores affects patch residence times and efficiency of parasitism. 

Poison frogs

Alongside community ecology of plant-insect interactions, I am interested in the ecology and evolution of Neotropical poison frogs (Dendrobatoidae).

Publications