Figure 1.

A cage contained a water dish (w) and two food dishes, one consisting of a nutritionally balanced (B) and the other deficient (D) food. Twice a day, we removed the food dishes and introduced new dishes. The Learning grasshoppers experienced a predictable environment: the two food types were always placed at the same sides, near the same colored card, and with the same flavor. The Random grasshoppers had a temporally varying environment: the location, background color, and flavor of each diet type was randomly determined on each food change. The figure depicts two examples to illustrate the protocol; see Methods for full details.