  Jean-Baptiste Lamarck was among first to suggest that certain acquired traits
may be heritable from parents to offspring. In this study, I examine whether
and what aspects of sensorimotor conditioning by parents prior to conception
may influence the behavior of subsequent generations in Drosophila. Using
genetic and anatomic techniques, I find that both first- and second-generation
offspring of parents who underwent prolonged olfactory training over multiple
days displayed a distinct response bias to the same specific trained odors. The
offspring displayed an enhanced anemotactic approach response to the trained
odors, however, and did not differentiate between orders based on whether
parental training was aversive or appetitive. Consequently, disruption of both
olfactory-receptor and dorsal-paired-medial neuron input into the mushroom
bodies abolished this change in offspring response, but disrupting synaptic
output from a/b neurons of the mushroom body themselves had little effect on
behavior even though they remained necessary for enacting newly trained
conditioned responses. These observations identify a unique transgenerational
dissociation between parentally-trained conditioned and unconditioned sensory
stimuli, and provide a putative neural basis for how sensorimotor experiences
in insects may bias the behavior of subsequent generations.
