To analyse dispersal of yeast strains by Drosophila we created special YPD-plates. These were made to ensure that the initial inoculum of each strain would not influence the cell counts of the dispersed cells. To create these plates, caps of screw cap eppendorf tubes were glued in a petri-dish, with sizes and positioning as shown in the figure (two small circles). The plates were subsequently filled with 35ml of YPD 2% agar, supplemented with 100 mg/l chloramphenicol. The caps were filled with 500 μl of the same medium.