Fig. 1.

Experimental mate preference arenas consisted of tygon tubing (0.79-mm internal diameter and 7.6 mm in length), fine plastic mesh, and two Eppendorf tubes. The single chooser was able to move throughout the length of the long corridor. The Eppendorf tubes were the cells (A and B) containing discriminatees of the opposite sex. Opaque tape on one side of each tube blocked visual contact between the discriminatees, one per cell during preference testing. The side of each Eppendorf cell connected to a longer corridor of tubing in which we placed focal individual choosers. Very fine plastic mesh prevented the discriminatees from moving into the corridor and the chooser from entering either of the cells. We divided each corridor into three regions (A and B in front of each Eppendorf cell, and C designating the space between them) designated by dark lines drawn on the surface of the tubing.