My name is Karen Muñoz-Cárdenas, I am a PhD student in the Population Biology group of the Institute for Biodiversity and Ecosystem Dynamics at the University of Amsterdam. I want to learn to use ecological theories such as apparent competition, to better understand the interactions in arthropod food webs associated with plants, and to improve biological pest control. I am interested in the use of alternative prey/food to improve biological control in commercial crops. It is well known that the presence of alternative food/prey on plants can be beneficial for predators: it allows the predators to survive, develop and reproduce when the target pest is absent and if both the pest and the alternative prey/food are available, predators might also benefit from a mixed diet, boosting their populations and increasing biological control. However, in some cases, like ornamentals in greenhouses, there is not enough alternative prey/food on the plants and the damage thresholds of the pests are very low, so it becomes feasible to add food on the plant (like pollen) or to use the belowground decomposer community as a source of alternative prey. I am trying to elucidate if it is possible to promote aboveground pest control by supplying alternative prey belowground. My study system is rose crops, which are attacked by thrips and whiteflies. Plant and litter-dwelling predators are used for biocontrol of these pests in roses in the Netherlands but they do not establish in the crop due to lack of alternative food/prey. I am interested particularly in this system because although it is known that these predators can feed on both the pest and the alternative prey/food, the effect of adding alternative prey/food to the system on the predators population dynamics remains to be investigated.