Most of us don’t really care about the learning and memory of insects, but if caterpillars can learn and remember it’s hard to argue livestock can’t. This study examines whether experiences at the larval stages in the tobacco hornworm can persist through pupation into adulthood.
Fifth instar tobacco hornworm caterpillars received an electrical shock paired with the odor of ethyl acetate to create a conditioned odor aversion. Researchers showed that larvae learned to avoid the odor, and that this aversion was still present in adults. The adult aversion came from training and did not result from carryover of chemicals from the larval environment because neither applying odorants to naive pupae nor washing the pupae of trained caterpillars changed their behavior.
Larvae trained in the third instar still showed odor aversion after two molts, as fifth instars, but did not avoid the odor as adults. Apparently, post-metamorphic recall involves regions of the brain that are not developed until later in the caterpillar’s life.
Reference: Blackiston, DJ, ES Casey, and MR Weiss. 2008. Retention of Memory through Metamorphosis: Can a Moth Remember What It Learned as a Caterpillar? PLoS ONE 3(3): e1736. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001736