Figure 3. Larvae conditioned with forward-paired shock+odor at fifth instar retain odor avoidance as adults.

Proportion of adult M. sexta choosing ambient air rather than EA in the Y choice apparatus after receiving one of five treatments: no exposure to odor or electric shock (N = 31), shock only (N = 23), odor only (N = 28), the forward pairing of shock+odor at fifth instar (N = 27), or forward pairing of shock+odor at third instar (N = 15). Only individuals that received the shock+odor pairing as fifth instar caterpillars maintained odor avoidance as adults. While individuals trained at third instar demonstrated odor aversion at fifth insta (Fig 2.), the behavior was lost during pupation. ** (p<0.01) indicates the value that differs significantly from random choice (dashed horizontal line) by a two-tailed binomial calculation. Values are means±SD.