Fig. 1.

Locomotor activity monitoring system. (A) Locomotor activity monitor (LAM16) as sold by Trikinetics Inc. The LAM16 monitor contains 32 channels. Each channel contains three infrared beams and their corresponding receptor. The wiring of the internal board of the monitors is arranged such that the interruption of one or more beams on each channel counts as a single activity event. (B) Water system assembly ensures that every individual has a constant supply of water. This assembly minimizes handling and refilling time compared with individual water supplies. A detailed description of this system has been provided in the Materials and methods. (C) Sampling tubes and honey candy. The sampling tube is a standard 15 ml centrifuge tube with holes for air and water system connection. The honey candy is first placed directly into the tube cap and then a piece of cheese-cloth is placed on top of the food. The cloth prevents spillage and spreading of the food throughout the tube, and thus prevents individuals from becoming stuck. (D) Fully assembled LAM system including the water system assembly and the sampling tubes.