Long- but not medium-term retention of olfactory memories in honeybees is impaired by actinomycin D and anisomycin

Although work in a wide variety of species and paradigms has demonstrated that long-term memory is sensitive to the blocking of protein synthesis, previous studies have suggested that the honeybee might represent an exception to this rule. Retention tested one day after training was not impaired by the inhibition of translation by cycloheximide. Using blockers of either transcription (actinomycin D) or translation (anisomycin), we present experiments that reconcile this unusual finding by testing over longer retention periods. Honeybees were conditioned to associate an odourant with a sucrose reward. Typically, this leads to stable retention over days. However, injection of either drug led to lower retention after 4 days, whereas retention after 2 or sometimes even 3 days was unaffected. This dissociates two forms of memory: a protein synthesis-independent, medium-term memory (up to 3 days) and a protein synthesis-dependent, long-term memory lasting for at least 4 days.