Worms are known to increase the frequency of turning and reversal events in response to removal of a food stimulus. This keeps the animal in a small area near the last observation of food. The increase in turning frequency is known to be regulated by dopamine and glutamate (Hills et al 2004).
We have found that the search strategy is modified by the spatial pattern of food that is experienced. Worms adapt quickly to new food environments, learning spatial patterns on short timescales. The dopamine deficient
cat-2 mutant is unable to learn different spatial patterns, suggesting that dopamine is required for spatial memory.
References
Hills T, Brockie PJ, Maricq AV (2004). Dopamine and glutamate control area-restricted search behavior in Caenorhabditis elegans. J Neurosci 24(5): 1217-1225.