Fig. 1.

1A: The “choice arena” consists of an upside down Petri dish. At the center, the arena connects to a cartridge (c) that holds the predatory mites. The cartridge is connected to the vacuum pump. Arrows indicate the direction of the radial airflow in the arena. Odors are applied on filter paper (gray circles).The choice arena is divided in the two sides by a thin layer of insect glue (thick black lines). 1B: Modified version of 1 A that can be fitted with two veils that hold a tomato or a bean leaf placed on moist cotton wool. Gauze covered holes connect the veils to the choice arena. A single mite is released into the center and from 30 min the time it spends in each of the odor fields (triangles in the lower panel) is measured