Farming relies heavily on the use of pesticides in order to maintain or even increase crop production. We now know, however, that over-use of pesticides has a strong and unwanted impact on the environment and on biodiversity. Thus, alternative solutions to better balance production and the environment have begun to emerge. The use of naturally-present predators of pests, such as ground beetles, for biological control is one of them. Ground beetles exhibit a diversity of feeding regimes (diets) ranging from strictly feeding on seeds to being generalist predators (seeds and animal prey). Since they mostly feed on the seeds of weeds and invertebrate pests they appear a good candidate for biological control. How they choose, or switch, between their prey types and how this choice is influenced by the environment and/or the personality of the individual predator is still not clearly understood. This is the aim of my Ph. D. thesis. I will start by looking at ground beetle food preferences using a two-stage experimental process. Initially, “no-choice” tests of food experiments will be done, which will be followed by “choice” tests in order to disentangle preference between different food types. We will look at how long it takes for one individual to find a prey and eat it with and without choice and if their choices are consistent when they have the choice. These tests will also allow us to investigate any possible competition that may exist between the two types of food, e.g. seeds and “meat”, and thus the potential for an antagonistic effect between these two ecosystem services. We will then repeat these experiments in more complex environments, e.g. mesocosms, and introduce intraspecific competition to test the robustness of our preliminary food preferences results. The role of learning and personality will also be examined in relation to food choice and constancy