Bay leaf extract is a chemotaxis repellent for C. elegans

Plants synthesize compounds that modulate animal nervous systems through various mechanisms, but the key interactions remain understudied. We used chemotaxis assays with the nematode <i>Caenorhabditis elegans</i> to test if plant extracts can be detected by the worm nervous system and which compounds induce behavioral responses. We found that <i>C. elegans</i> avoid the extract of bay leaves ( <i>Laurus nobilis</i> ). Subsequent testing of known bay leaf compounds identified cadinene and eugenol as key molecules that may mediate the repulsion effect. These experiments were conducted by undergraduate students in an upper-division laboratory course, providing practical research experiences and new insights into plant-animal interactions.