Dopamine signaling regulates predator-driven behavioral changes in Caenorhabditis elegans

Abstract

AbstractPrey respond to predators by altering their behavior to optimize their own fitness and survival. We probe the interactions between Caenorhabditis elegans and its naturally cohabiting predator Pristionchus uniformis to reveal the pathways driving changes in prey behavior. C. elegans, which normally lays its eggs on a bacteria lawn, alters the location of the eggs away from a lawn occupied by the predator. Also, these eggs are laid close to thin streaks of bacteria, which are likely the result of the prey moving some bacteria away from the dense lawn as they exit the lawn. We confirm that this change in egg location requires a predator capable of biting, but not predator secretions. Next, we find that mutants in dopamine and serotonin synthesis do not display this predator-evoked change in egg location. We also show that dopamine is primarily released from CEP dopaminergic neurons, and requires multiple dopamine receptors (DOP-1, DOP-2, and DOP-3) to alter prey behavior. Predator-exposed prey continue to lay their eggs near the thin bacterial streaks and away from the dense lawn even after the predator is removed, indicating a form of learning. Finally, exogenous dopamine can rescue the behavioral deficits in a dopamine-deficient mutant, suggesting that predator-exposure might cause an increase in prey dopamine. Together, we show that dopamine alters prey foraging strategy upon predator exposure, implying a role for this pathway in defensive behaviors.